OFFER TO PURCHASE

BancFirst Corporation (the “Company,” “we” or “us”) hereby offers to purchase up to 500,000 shares of its common stock, $1.00 par value per share (the “Common Stock”), including the associated preferred stock purchase rights (together with the Common Stock, the “Shares”), at a purchase price of not greater than $45.00 nor less than $39.50 per Share, net to the seller in cash, less any applicable withholding taxes and without interest, upon the terms and subject to the conditions described in this Offer to Purchase and in the related Letter of Transmittal (which together, as they may be amended or supplemented from time to time, constitute the “Offer”). We will select the lowest price per Share (in multiples of $0.25) (the “Purchase Price”) that will allow us to purchase 500,000 Shares or, if a lesser number is properly tendered, all Shares that are properly tendered and not properly withdrawn. All Shares acquired in the Offer will be acquired at the same price regardless of whether the shareholder tendered at a lower price. However, because of the proration, “odd lot” priority and conditional tender provisions described in this Offer to Purchase, all of the Shares tendered at or below the Purchase Price may not be purchased if more than the number of Shares we seek are properly tendered. Shares tendered but not purchased in the Offer will be returned to the tendering shareholders at our expense promptly after the expiration of the Offer. See Sections 1 and 3.

In the event that more than 500,000 Shares are tendered in the Offer at or below the Purchase Price, we may exercise our right to amend the Offer to purchase up to an additional 2% of our outstanding Shares without extending the Expiration Date. We also expressly reserve the right, in our sole discretion, to purchase additional Shares, subject to applicable law. See Sections 1 and 15.

Unless the context requires otherwise, all references to Shares shall include the associated preferred stock purchase rights issued pursuant to the Rights Agreement, dated as of February 25, 1999, between BancFirst Corporation and BancFirst, as Rights Agent. All Shares tendered and purchased will include such associated preferred stock purchase rights. No additional consideration will be paid for the associated rights.

The Offer is not conditioned upon the receipt of financing or any minimum number of Shares being tendered. The Offer is, however, subject to other conditions. See Section 7.

The Shares are listed on the Nasdaq Global Select Market (the “Nasdaq”) and trade under the symbol “BANF.” On August 1, 2007, the last full trading day before the announcement of the Offer, the last reported sale price of the Shares was $40.59 per Share. Shareholders are urged to obtain current market quotations for the Shares before deciding whether to tender their Shares. See Section 8.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of this transaction or passed upon the merits or fairness of such transaction or passed upon the adequacy or accuracy of the information contained in this Offer to Purchase. Any representation to the contrary is a criminal offense.

OUR BOARD OF DIRECTORS HAS APPROVED THE OFFER. HOWEVER, NEITHER WE NOR OUR BOARD OF DIRECTORS NOR THE DEALER MANAGER, INFORMATION AGENT OR DEPOSITARY MAKES ANY RECOMMENDATION TO YOU AS TO WHETHER TO TENDER OR REFRAIN FROM TENDERING YOUR SHARES OR AS TO THE PURCHASE PRICE OR PURCHASE PRICES AT WHICH YOU MAY CHOOSE TO TENDER THEM. YOU MUST MAKE YOUR OWN DECISION AS TO WHETHER TO TENDER YOUR SHARES AND, IF SO, HOW MANY SHARES TO TENDER AND THE PRICE OR PRICES AT WHICH YOU WILL TENDER THEM. IN DOING SO, YOU SHOULD READ CAREFULLY THE INFORMATION IN THIS OFFER TO PURCHASE AND IN THE RELATED LETTER OF TRANSMITTAL, INCLUDING THE PURPOSES AND EFFECTS OF THE OFFER. SEE SECTION 2. YOU SHOULD DISCUSS WHETHER TO TENDER YOUR SHARES WITH YOUR BROKER, IF ANY, OR OTHER FINANCIAL AND TAX ADVISORS.

NONE OF OUR DIRECTORS AND EXECUTIVE OFFICERS INTENDS TO TENDER ANY OF THEIR SHARES IN THE OFFER, EXCEPT FOR ROBERT A. GREGORY, A DIRECTOR, WHO INTENDS TO TENDER 3,000 SHARES, AND MIKE ROGERS, EXECUTIVE VICE PRESIDENT—HUMAN RESOURCES, WHO INTENDS TO TENDER 4,000 SHARES.

If you want to tender all or part of your Shares, you must do one of the following before the Offer expires:

If you want to tender your Shares but (a) the certificates for your Shares are not immediately available or cannot be delivered to the Depositary by the expiration of the Offer, (b) cannot comply with the procedure for book-entry transfer or (c) your other required documents cannot be delivered to the Depositary, by the expiration of the Offer, you may still tender your Shares if you comply with the guaranteed delivery procedure described in Section 3 of this Offer to Purchase.

If you wish to maximize the chance that your Shares will be purchased by us, you should check the box in the section of the Letter of Transmittal captioned “Shares Tendered at a Price Determined Pursuant to the Offer.” If you agree to accept the purchase price determined in the Offer, your Shares will be deemed to be tendered at the minimum price of $39.50 per share. You should understand that this election may lower the purchase price paid for all purchased Shares in the Offer and could result in your Shares being purchased at the minimum price of $39.50 per Share. The lower end of the price range for the Offer is below the closing market price for the Shares on August 1, 2007, the last full trading day prior to the announcement of the Offer, when the closing market price on the Nasdaq was $40.59. See Section 3.

TO TENDER SHARES PROPERLY, OTHER THAN SHARES REGISTERED IN THE NAME OF A BROKER, DEALER, COMMERCIAL BANK, TRUST COMPANY OR OTHER NOMINEE, YOU MUST PROPERLY COMPLETE AND DULY EXECUTE THE LETTER OF TRANSMITTAL, INCLUDING THE SECTION RELATING TO THE PRICE AT WHICH YOU ARE TENDERING YOUR SHARES.

WE ARE NOT MAKING THE OFFER TO, AND WILL NOT ACCEPT ANY TENDERED SHARES FROM, SHAREHOLDERS IN ANY JURISDICTION WHERE IT WOULD BE ILLEGAL TO DO SO. HOWEVER, WE MAY, AT OUR DISCRETION, TAKE ANY ACTIONS NECESSARY FOR US TO MAKE THE OFFER TO SHAREHOLDERS IN ANY SUCH JURISDICTION. IN ANY JURISDICTION THE SECURITIES OR BLUE SKY LAWS OF WHICH REQUIRE THE TENDER OFFER TO BE MADE BY A LICENSED BROKER OR DEALER, THE TENDER OFFER IS BEING MADE ON OUR BEHALF BY ONE OR MORE REGISTERED BROKERS OR DEALERS THAT ARE LICENSED UNDER THE LAWS OF SUCH JURISDICTION.

WE HAVE NOT AUTHORIZED ANY PERSON TO MAKE ANY RECOMMENDATION ON OUR BEHALF AS TO WHETHER YOU SHOULD TENDER OR REFRAIN FROM TENDERING YOUR SHARES OR AS TO THE PRICE OR PRICES AT WHICH YOU MAY CHOOSE TO TENDER YOUR SHARES IN THE OFFER. YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED IN THIS OFFER TO PURCHASE AND IN THE RELATED LETTER OF TRANSMITTAL OR TO WHICH WE HAVE REFERRED YOU. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE YOU WITH INFORMATION OR TO MAKE ANY REPRESENTATION IN CONNECTION WITH THE OFFER OTHER THAN THOSE CONTAINED IN THIS OFFER TO PURCHASE OR IN THE RELATED LETTER OF TRANSMITTAL. IF ANYONE MAKES ANY RECOMMENDATION OR GIVES ANY INFORMATION OR REPRESENTATION, YOU MUST NOT RELY UPON THAT RECOMMENDATION, INFORMATION OR REPRESENTATION AS HAVING BEEN AUTHORIZED BY US, THE DEALER MANAGER, THE DEPOSITARY OR THE INFORMATION AGENT.

Questions and requests for assistance may be directed to MacKenzie Partners, Inc., the Information Agent for the Offer, or Friedman, Billings, Ramsey & Co., Inc., the Dealer Manager for the Offer, in each case at the telephone numbers and addresses set forth on the back cover of this Offer to Purchase. You may request additional copies of this Offer to Purchase and other Offer documents from the Information Agent at the telephone number and address on the back cover of this Offer to Purchase.

If you have any questions regarding the Offer, please contact MacKenzie Partners, Inc. at (212) 929-5500 (collect) or (800)322-2885 (toll-free), or Friedman, Billings, Ramsey & Co., Inc. at (703) 312-9733 or at (800) 532-2268 (toll free).

SUMMARY TERM SHEET

We are providing this summary term sheet for your convenience. It highlights the most important information from this Offer to Purchase. To understand the Offer fully and for a more complete description of the terms of the Offer, you should read carefully this entire Offer to Purchase, the Letter of Transmittal and the other documents that constitute part of the Offer. We have included references to the sections of this Offer to Purchase where you will find a more complete description of the topics in this summary.

Who is offering to purchase Shares?

BancFirst Corporation is offering to purchase your Shares, which include the associated preferred stock purchase rights.

How many Shares is BancFirst Corporation offering to purchase?

We are offering to purchase up to 500,000 Shares (representing approximately 3.2% of our outstanding Shares as of July 31, 2007) that shareholders properly tender in the Offer or, if a lesser number of Shares are validly tendered, such lesser number of Shares as are properly tendered and not properly withdrawn, subject to the “odd lot” and proration provisions described in this Offer to Purchase. Each Share includes an associated preferred stock purchase right that we will acquire with each Share that we purchase. See Sections 1 and 2.

If more than 500,000 Shares (or such greater number of Shares as we may elect to purchase, subject to applicable law) are properly tendered, all Shares tendered at or below the Purchase Price will be purchased on a pro rata basis, subject to the odd lot priority and conditional tender provisions described herein. The Offer is not conditioned on any minimum number of Shares being tendered by shareholders. See Section 1.

What will be the purchase price for the Shares and what will be the form of payment?

We are conducting this Offer through a procedure called a “modified Dutch auction.” This procedure allows you to select the price within a price range specified by us at which you are willing to sell your Shares. The price range for the Offer is $39.50 to $45.00 per Share. See Section 1.

We will select the lowest purchase price (the “Purchase Price”) that will allow us to buy 500,000 Shares or, if a lesser number of Shares is properly tendered, all Shares that are properly tendered and not properly withdrawn. The lower end of the price range for the Offer is below the closing market price for the Shares on August 1, 2007, the last full trading day prior to the announcement of the Offer, when the closing market price on the Nasdaq was $40.59. We will determine the Purchase Price as promptly as practicable after the Offer expires. For purposes of determining the Purchase Price, those Shares that are tendered by shareholders agreeing to accept the Purchase Price determined in the Offer, as described below, will be deemed to be tendered at the minimum price of $39.50. See Section 1.

All Shares that we purchase will be purchased at the Purchase Price, even if you have selected a lower price, but we will not purchase any Shares above the Purchase Price we determine. If you wish to maximize the chance that your Shares will be purchased, you should check the box in the section on the Letter of Transmittal indicating that you will accept the Purchase Price we determine. If you agree to accept the Purchase Price determined in the Offer, your Shares will be deemed to be tendered at the minimum price of $39.50 per Share.

You should understand that this election could result in your Shares being purchased at the minimum price of $39.50 per Share. The lower end of the price range for the Offer is below the closing market price for the Shares on August 1, 2007, the last full trading day prior to the announcement of the Offer, when the closing market price on the Nasdaq was $40.59. See Section 1.

If your Shares are purchased in the Offer, you will receive the Purchase Price, net to the seller in cash, less any applicable withholding taxes and without interest, promptly after the Expiration Date. Under no circumstances will we pay interest on the Purchase Price, including but not limited to, by reason of any delay in making payment. The Offer is scheduled to expire at 5:00 p.m., New York City time, on September 4, 2007, unless the Offer is extended by us. See Sections 1 and 5.

What are the “associated preferred stock purchase rights”?

Each time we issue a Share, we issue to the holder of the Share one preferred stock purchase right pursuant to the Rights Agreement, dated as of February 25, 1999, between BancFirst Corporation and BancFirst, as Rights Agent (the “Rights Agreement”), which is filed as an exhibit to our Tender Offer Statement on Schedule TO relating to the Offer. Unless the context otherwise requires, all references to Shares include the associated preferred stock purchase rights and a tender of Shares will include a tender of the associated preferred stock purchase rights. No additional consideration will be paid for the associated rights. See Section 1. The Rights Agreement provides that no Person shall become an “Acquiring Person” under the Rights Agreement as the result of a reduction in the number of Shares of Common Stock outstanding due to, for example, the repurchase of Shares of Common Stock by BancFirst Corporation, unless and until such Person, after becoming aware that such Person has become the beneficial owner of 15% or more of the then outstanding Shares of Common Stock, acquires beneficial ownership of, or commences a tender or exchange offer for, any additional Shares of Common Stock. See Section 8.

How will BancFirst Corporation pay for the Shares?

Assuming that the maximum number of Shares is tendered in the Offer and the Purchase Price is an amount between $39.50 and $45.00 per Share, the aggregate purchase price for the Shares pursuant to the Offer will be between $19,750,000 and $22,500,000. We will pay for the Shares purchased in the Offer, and the related fees and expenses, from our cash reserves as well as dividend payments from our wholly owned bank subsidiary, BancFirst. See Sections 5 and 9.

How long do I have to tender my Shares?

You may tender your Shares until the Offer expires. The Offer will expire on September 4, 2007 at 5:00 p.m., New York City time, unless we extend the Offer. We may choose to extend the Offer in our sole discretion at any time. We cannot assure you, however, that we will extend the Offer or, if we extend it, for how long. See “Introduction” and Sections 1 and 15.

If a broker, dealer, commercial bank, trust company or other nominee holds your Shares, it is likely that they have an earlier deadline for accepting the Offer. See Section 3.

Can the Offer be extended, amended or terminated and, if so, under what circumstances?

We can extend or amend the Offer in our sole discretion. If we extend the Offer, we will delay the acceptance of any Shares that have been tendered. We can also terminate the Offer under certain circumstances. See Sections 7 and 15.

How will I be notified if the Offer is extended or amended?

If the Offer is extended, we will make a public announcement of the extension no later than 9:00 a.m., New York City time, on the first business day after the previously scheduled Expiration Date. We will announce any amendment to the Offer by making a public announcement of the amendment. See Section 15.

What is the purpose of the Offer?

We believe that the repurchase of Shares is consistent with our long-term goal of maximizing shareholder value. Our management and Board of Directors have evaluated the Company’s operations, financial condition, capital needs, strategy and expectations for the future and believe that the Offer is a prudent use of our financial resources given our business profile and assets, and that repurchasing our Shares is an attractive use of capital and an efficient means to provide liquidity to our shareholders. We currently anticipate that we will have adequate cash generating capacity, and we expect that our current cash balances, anticipated cash flows from operations and borrowing capacity exceed our capital requirements for normal operations, capital expenditures and acquisitions and other opportunities for growth that may arise. The Offer represents the opportunity for us to return cash to shareholders who elect to tender their Shares without the usual transaction costs associated with open market sales, while at the same time increasing non-tendering shareholders’ proportionate interest in us and thus in our future earnings and assets at no additional cost to them. We believe the Offer will be accretive to currently projected earnings per share, although there can be no assurance of this. See Section 2.

Are there any conditions to the Offer?

Our obligation to purchase Shares tendered depends upon a number of conditions that must be satisfied or waived by us, prior to the Expiration Date, including but not limited to:

•

No legal action shall have been instituted, threatened in writing, pending or taken that challenges or affects the Offer or materially and adversely affects our and our subsidiaries’ business, properties, assets, liabilities, capitalization, shareholders’ equity, financial condition, operations, results of operations or prospects or otherwise materially impairs the contemplated future conduct of our business or our ability to exercise full rights of ownership or purchase and hold some or all of the Shares purchased in the Offer;

•

No general suspension of trading in, or limitation on prices for, securities on any national securities exchange or in the over-the-counter markets in the United States or the declaration of a banking moratorium or any suspension of payment in respect of banks in the United States shall have occurred;

•

No changes in the general political, market, economic or financial conditions in the United States or abroad that could reasonably be expected to materially and adversely affect our or our subsidiaries’ business, properties, assets, liabilities, capitalization, shareholders’ equity, financial condition, operations, results of operations or prospects, or otherwise materially impair the contemplated future conduct of our business shall have occurred;

•

No commencement or escalation of war, armed hostilities or other international or national calamity, including, but not limited to, an act of terrorism, shall have occurred directly or indirectly involving the United States on or after August 3, 2007 nor shall any material escalation, on or after August 3, 2007, of any war or armed hostilities which had commenced prior to August 3, 2007 have occurred;

•

No decrease of more than 10% in the market price for the Shares or in the Dow Jones Industrial Average, New York Stock Exchange Index, NASDAQ Composite Index or the Standard & Poor’s 500 Composite Index measured from the close of trading on August 1, 2007 shall have occurred;

•

No person shall have commenced, proposed, announced, made or have publicly disclosed a tender or exchange offer (other than this Offer), merger, acquisition, business combination or other similar transaction involving us or any of our subsidiaries nor shall we have entered into a definitive agreement

or an agreement in principle with any person with respect to a merger, acquisition, business combination or other similar transaction, other than in the ordinary course of business;

•

No person (including a group) shall have acquired or proposed to acquire beneficial ownership of more than 5% of the outstanding Shares (other than anyone who publicly disclosed such ownership in a filing with the Securities and Exchange Commission (the “SEC”) before August 3, 2007). No person or group which has made such a filing before August 3, 2007 shall acquire or publicly announce its proposal to acquire an additional 1% or more of our outstanding Shares. In addition, no new group shall have been formed that beneficially owns (as a group) more than 5% of our outstanding Shares;

•

No material adverse change in our and our subsidiaries’ business, properties, assets, liabilities, capitalization, shareholders’ equity, financial condition, operations, results of operations or prospects shall have occurred; and

•

No determination shall have been made by us that the consummation of the Offer may cause the reasonable likelihood of the Shares either (1) to be held of record by less than 300 persons or (2) to be delisted from the Nasdaq or to be eligible for deregistration under the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

The Offer is subject to a number of other conditions described in greater detail in Section 7.

How will the Offer affect the number of Shares outstanding and the number of record holders of BancFirst Corporation?

As of July 31, 2007, we had 15,724,536 issued and outstanding shares of Common Stock. The 500,000 Shares that we are offering to purchase pursuant to the Offer represent approximately 3.2% of our outstanding Shares (assuming the Offer is fully subscribed) as of July 31, 2007. If the Offer is fully subscribed, we will have 15,224,536 Shares outstanding following the purchase of Shares tendered in the Offer. The actual number of Shares outstanding will depend on the number of Shares tendered and purchased in the Offer. See Section 2.

To the extent any of our shareholders tender their Shares in full and that tender is accepted in full, the number of our record holders would be reduced. See “Introduction” and Section 14.

Shareholders who do not have their Shares purchased in the Offer will realize a proportionate increase in their relative ownership interest in BancFirst Corporation. See Section 2.

How do I tender my Shares?

•

If you hold your Shares in your own name as a holder of record and decide to tender your Shares, you must: deliver a completed and signed Letter of Transmittal or an Agent’s Message to the Depositary before 5:00 p.m., New York City time, on September 4, 2007, or such later time and date to which we may extend the Offer;

•

If you hold your Shares in a brokerage account or otherwise through a broker, dealer, commercial bank, trust company or other nominee (i.e., in “street name”), you must contact your broker, dealer, commercial bank, trust company or other nominee if you wish to tender your Shares. See Section 3 and the instructions to the Letter of Transmittal;

•

If you are an institution participating in the Depository Trust Company, tender your Shares according to the procedure for book-entry transfer described in Section 3 of this Offer to Purchase;

•

If you are a holder of vested options to purchase Shares under the Company’s equity compensation plans, you may exercise your vested options and tender any of the Shares issued upon exercise; or

•

if you are a participant in our equity-based retirement plans, you must follow the instructions in the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” sent separately to each eligible participant in the plans.

If you want to tender your Shares, but:

•

the certificates for your Shares are not immediately available or cannot be delivered to the Depositary by the expiration of the Offer;

•

you cannot comply with the procedure for book-entry transfer by the expiration of the Offer; or

•

your other required documents cannot be delivered to the Depositary by the expiration of the Offer;

you can still tender your Shares if you comply with the guaranteed delivery procedure described in Section 3.

You may contact the Information Agent, the Dealer Manager or your broker for assistance. The contact information for the Information Agent and Dealer Manager is on the back cover page of this Offer to Purchase. See Section 3 and the instructions to the Letter of Transmittal.

How do holders of vested stock options for Shares participate in the Offer?

If you hold vested but unexercised options, you may exercise such options in accordance with the terms of the applicable stock option plans and your awards and tender the Shares received upon such exercise in accordance with this Offer. An exercise of an option cannot be revoked for any reason even if Shares received upon the exercise thereof and tendered in the Offer are not purchased in the Offer. See Section 3. You should evaluate this Offer to Purchase carefully to determine if participation would be advantageous to you, based on your stock option exercise prices, the date of your stock option grants, the years left to exercise your options and the provisions for pro rata purchases by BancFirst Corporation described in Section 1. We strongly encourage you to discuss the Offer with your tax advisor or broker. Holders of unvested stock awards may not tender Shares or Shares represented by such interests, unless they are fully vested.

How do participants in our retirement plans whose shares are held by a plan trustee participate in the Offer?

Participants in our equity-based retirement plans whose shares are held by a trustee may not use the Letter of Transmittal to direct the tender of shares allocated to units they hold in the equity unit funds under the plans, but instead must follow the instructions in the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” sent separately to each eligible participant in the plans. These instructions require that a plan participant who wishes to tender shares under the plan complete the Direction Form as directed in the letter. The deadline for submitting Direction Forms will be 5:00 pm, New York City Time, on Tuesday, September 4, 2007, unless we extend the Offer, in which case you may submit your Direction Form until 5:00 pm, New York City Time, on the expiration date of the Offer, as extended. See Section 3. Participants in these two retirement plans should be aware that the plans are prohibited from selling shares to us for a price less than the prevailing market price. Accordingly, if you elect to tender Shares allocated to units you hold in the equity funds under either of these plans, and the last-sale-eligible-trade price of our Common Stock on Nasdaq on September 4, 2007 is more than the price at which you tendered Shares, your Shares will not be eligible for the Offer, and your tender of plan Shares automatically will be withdrawn.

May I tender only a portion of the Shares that I hold?

Yes. You do not have to tender all of the Shares that you own to participate in the Offer.

Until what time can I withdraw previously tendered Shares?

You may withdraw your tendered Shares at any time before 5:00 p.m., New York City time, on September 4, 2007, or such later time and date to which we may extend the Offer. In addition, unless we have already accepted your tendered Shares for payment, you may withdraw your tendered Shares at any time after 11:59 p.m., New York City time, on October 1, 2007. See Section 4.

How do I withdraw Shares previously tendered?

You must deliver on a timely basis a written or facsimile notice of your withdrawal to the Depositary at the address appearing on the back cover page of this Offer to Purchase. To properly withdraw Shares, you must deliver a written notice of withdrawal, which must specify your name, the number of Shares to be withdrawn and the name of the registered holder of such Shares, to the Depositary while you still had the right to withdraw Shares. If you have used more than one Letter of Transmittal or have otherwise tendered Shares in more than one group of Shares, you may withdraw Shares using either separate notices of withdrawal or a combined notice of withdrawal, so long as the required information is included. Some additional requirements apply if your Shares have been tendered under the procedure for book-entry transfer set forth in Section 3. If you have tendered your Shares by giving instructions to a bank, broker, dealer, trust company or other nominee, you must instruct the nominee to arrange for the withdrawal of your Shares. See Section 4.

In what order will tendered Shares be purchased? Will tendered Shares be prorated? What happens if more than 500,000 Shares are tendered at or below the Purchase Price?

If more than 500,000 Shares (or such greater number of Shares as we may elect to purchase, subject to applicable law) are properly tendered and not properly withdrawn, we will purchase Shares in the following order of priority:

•

First, we will purchase all Odd Lots (as defined in Section 1) of less than 100 Shares at the Purchase Price from shareholders who properly tender all of their Shares at or below the Purchase Price and who do not properly withdraw them before the Expiration Date;

•

Second, after purchasing all the Odd Lots that were properly tendered at or below the Purchase Price, subject to the conditional tender provisions described in Section 6, we will purchase Shares at the Purchase Price from all other holders who properly tender Shares at or below the Purchase Price and who do not properly withdraw them before the Expiration Date, on a pro rata basis, with appropriate adjustments to avoid purchases of fractional Shares, until we have acquired the number of Shares that we have offered to purchase (except for shareholders who tendered Shares conditionally for which the condition was not satisfied); and

•

Third, only if necessary to permit us to purchase 500,000 Shares (or such greater number of Shares as we may elect to purchase, subject to applicable law), we will purchase Shares at the Purchase Price from shareholders who have validly tendered Shares at or below the Purchase Price conditionally (for which the condition was not initially satisfied) by random lot, to the extent feasible. To be eligible for purchase by random lot, shareholders whose Shares are conditionally tendered must have properly tendered all of their Shares and not properly withdrawn them before the Expiration Date.

Therefore, we may not purchase all of the Shares that you tender even if you tender them at or below the Purchase Price. See Sections 1 and 6.

If I own fewer than 100 Shares and I tender all of my Shares, will I be subject to proration?

If you own beneficially or of record fewer than 100 Shares in the aggregate, you properly tender all of these Shares at or below the Purchase Price and do not properly withdraw them before the Expiration Date, and you complete the section entitled “Odd Lots” in the Letter of Transmittal and, if applicable, in the Notice of Guaranteed Delivery, we will purchase all of your Shares without subjecting them to the proration procedure. See Section 1.

Has BancFirst Corporation or its Board of Directors adopted a position on the Offer?

Our Board of Directors has approved the Offer. However, neither we nor the Board of Directors, the Dealer Manager, the Information Agent or the Depositary makes any recommendation to you as to whether you should tender or refrain from tendering your Shares or as to the price or prices at which you may choose to tender your Shares. You must make your own decision as to whether to tender your Shares and, if so, how many Shares to tender and the price or prices at which you tender your Shares. In doing so, you should read carefully the information in this Offer to Purchase and the Letter of Transmittal.

Will directors, officers or affiliates of BancFirst Corporation tender Shares in the Offer?

None of our directors and executive officers intends to tender any of their shares in the Offer, except for Robert A. Gregory, a director, who intends to tender 3,000 shares, and Mike Rogers, Executive Vice President-Human Resources, who intends to tender 4,000 shares. As a result, the Offer will increase the proportional holdings of our directors and executive officers, other than Messrs. Gregory and Rogers. Our directors and executive officers may, in compliance with applicable law, sell their shares in open market transactions at prices that may or may not be more favorable than the purchase price to be paid to our shareholders in the Offer. See Section 11.

Does BancFirst Corporation intend to repurchase any Shares other than pursuant to the Offer during or after the Offer?

Our Board of Directors has authorized the purchase of up to 1,520,362 Shares of the Company’s outstanding Common Stock under an open-market stock repurchase program adopted in November 1999, under which 233,052 Shares may yet be purchased as of July 31, 2007. However, Rule 13e–4(f) under the Exchange Act prohibits us from purchasing any Shares, other than in the Offer, until at least ten business days have elapsed after the Expiration Date. Accordingly, any additional purchases outside the Offer may not be consummated until at least ten business days have elapsed after the Expiration Date. See Sections 2 and 17.

What will happen if I do not tender my Shares?

Shareholders who choose not to tender will own a greater percentage ownership of our outstanding Shares following the consummation of the Offer. See Section 2.

When and how will BancFirst Corporation pay for the Shares I tender that are accepted for purchase?

We will pay the Purchase Price, without interest, for the Shares we purchase promptly after the expiration of the Offer and the acceptance of the Shares for payment. We will pay for the Shares accepted for purchase by depositing the aggregate Purchase Price with the Depositary promptly after the expiration of the Offer. The Depositary will act as your agent and will transmit to you the payment for all of your Shares accepted for payment. See Section 5.

What is the recent market price for the Shares?

On August 1, 2007, the last full trading day before announcement of the Offer, the last reported sale price per Share on the Nasdaq was $40.59 per Share. The lower end of the price range for the Offer is below this last reported price per Share. You are urged to obtain current market quotations for the Shares before deciding whether to tender your Shares. See Section 8.

Will I have to pay brokerage fees and commissions if I tender my Shares?

If you are a holder of record of your Shares and you tender your Shares directly to the Depositary, you will not incur any brokerage fees or commissions. If you hold your Shares through a broker, dealer, commercial bank, trust company or other nominee and your broker tenders Shares on your behalf, your broker may charge you a fee for doing so. We urge you to consult your broker, dealer, commercial bank, trust company or other nominee to determine whether any charges will apply. See Section 5.

What are the United States federal income tax consequences if I tender my Shares?

If you are a U.S. Holder (as defined in Section 13), the receipt of cash for your tendered Shares generally will be treated for United States federal income tax purposes either as (a) a sale or exchange eligible for capital gain or loss treatment or (b) a dividend. See Section 13. If you are a foreign shareholder (as defined in Section 13), the payment of cash for your tendered Shares may be subject to United States federal income tax withholding. See Section 3.

Note that special tax rules will apply with respect to Shares tendered through our retirement plans. Retirement plan participants should refer to the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan.” Please consult your personal tax advisor to determine how this will apply to you.

Will I have to pay stock transfer tax if I tender my Shares?

If you instruct the Depositary in the Letter of Transmittal to make the payment for the Shares to the registered holder, you will not incur any domestic stock transfer tax. See Section 5.

What is the accounting treatment of the Offer?

The accounting for our purchase of Shares in the Offer will result in a reduction of our shareholders’ equity in an amount equal to the aggregate purchase price of the Shares we purchase and a corresponding reduction in cash and cash equivalents. See Section 2.

Whom do I contact if I have questions about the Offer?

For additional information or assistance, you may contact MacKenzie Partners, Inc., the Information Agent for the Offer, or Friedman, Billings, Ramsey & Co., Inc., the Dealer Manager for the Offer, in each case at the telephone numbers and addresses set forth on the back cover of this Offer to Purchase. You may request additional copies of the Offer to Purchase, the Letter of Transmittal and other Offer documents from the Information Agent at the telephone number and address on the back cover of the Offer to Purchase.

If a retirement plan participant has any questions relating to the Offer or the number of Shares allocated to units they hold in the equity unit funds held in his or her plan account, the participant should contact the party set forth in the the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” sent separately to each eligible participant in the plans.

This Offer to Purchase and the documents incorporated by reference in this Offer to Purchase may contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E under the Exchange Act. We have used the words “may,” “will,” “expect,” “could,” “anticipate,” “believe,” “estimate,” “plan,” “intend” and similar expressions in this Offer to Purchase and the documents incorporated by reference in this Offer to Purchase to identify forward-looking statements. We have based these forward-looking statements on our current views with respect to future events and financial performance. Actual results could differ materially from those projected in the forward-looking statements. These forward-looking statements are subject to risks, uncertainties and assumptions, including, among other things:

All subsequent written and oral forward-looking statements concerning our Offer or other matters addressed in this document and attributable to us or any person acting on our behalf are qualified by these cautionary statements.

You should not put undue reliance on any forward-looking statements. You should understand that many important factors, including those discussed herein or in the documents incorporated herein by reference, could cause our results to differ materially from those expressed or suggested in any forward-looking statements. Except as required by law, we do not undertake any obligation to publicly release any revisions to these forward-looking statements to reflect events or circumstances that occur after the date of this Offer to Purchase or to reflect the occurrence of unanticipated events.

Notwithstanding anything in this Offer to Purchase, the Letter of Transmittal or any document incorporated by reference into this Offer to Purchase, the safe harbor protections of the Private Securities Litigation Reform Act of 1995, do not apply to statements made in connection with a tender offer.

BancFirst Corporation hereby offers to purchase up to 500,000 Shares of its Common Stock, including the associated preferred stock purchase rights, or such lesser number of Shares as are properly tendered and not properly withdrawn at a Purchase Price not greater than $45.00 nor less than $39.50 per Share, net to the seller in cash, less any applicable withholding taxes and without interest. We will select the lowest price per Share (in multiples of $0.25) that will allow us to purchase 500,000 Shares or, if a lesser number is properly tendered, all Shares that are properly tendered and not properly withdrawn. All Shares acquired in the Offer will be acquired at the same price regardless of whether the shareholder tendered at a lower price. Our Offer is being made upon the terms and subject to the conditions set forth in this Offer to Purchase and in the related Letter of Transmittal which, as amended or supplemented from time to time, together constitute the Offer.

Only Shares properly tendered at prices at or below the Purchase Price we select, and not properly withdrawn, will be purchased. However, because of the proration, “odd lot” priority and conditional tender provisions described in this Offer to Purchase, all of the Shares tendered at or below the Purchase Price we select will not be purchased if more than the number of Shares we seek are tendered. We will return any Shares that are tendered at prices in excess of the Purchase Price we select and Shares that we do not purchase because of proration or conditional tenders promptly following the Expiration Date. See Section 3.

Shareholders must complete the section of the Letter of Transmittal relating to the price at which they are tendering Shares in order to properly tender Shares.

The Offer is not conditioned on any minimum number of Shares being tendered. Our obligation to accept, and pay for, Shares validly tendered pursuant to the Offer is conditioned upon satisfaction or waiver of the conditions set forth in Section 7.

OUR BOARD OF DIRECTORS HAS APPROVED THE OFFER. HOWEVER, NEITHER WE NOR OUR BOARD OF DIRECTORS, THE DEALER MANAGER, THE INFORMATION AGENT OR THE DEPOSITARY MAKES ANY RECOMMENDATION TO YOU AS TO WHETHER TO TENDER OR REFRAIN FROM TENDERING YOUR SHARES OR AS TO THE PRICE OR PRICES AT WHICH YOU MAY CHOOSE TO TENDER YOUR SHARES. YOU MUST MAKE YOUR OWN DECISION AS TO WHETHER TO TENDER YOUR SHARES AND, IF SO, HOW MANY SHARES TO TENDER AND THE PRICE OR PRICES AT WHICH YOU WILL TENDER THEM. IN DOING SO, YOU SHOULD READ CAREFULLY THE INFORMATION IN THIS OFFER TO PURCHASE AND IN THE RELATED LETTER OF TRANSMITTAL, INCLUDING THE PURPOSES AND EFFECTS OF THE OFFER. SEE SECTION 2. YOU SHOULD DISCUSS WHETHER TO TENDER YOUR SHARES WITH YOUR BROKER, IF ANY, OR OTHER FINANCIAL AND TAX ADVISORS.

NONE OF OUR DIRECTORS, EXECUTIVE OFFICERS AND AFFILIATES HAS ADVISED US THAT THEY INTEND TO TENDER ANY SHARES OWNED BY THEM IN THE OFFER, EXCEPT FOR ROBERT A. GREGORY, A DIRECTOR, WHO INTENDS TO TENDER 3,000 SHARES, AND MIKE ROGERS, EXECUTIVE VICE PRESIDENT—HUMAN RESOURCES, WHO INTENDS TO TENDER 4,000 SHARES. ACCORDINGLY, IF WE COMPLETE THE OFFER THE PROPORTIONAL HOLDINGS OF OUR DIRECTORS, EXECUTIVE OFFICERS AND AFFILIATES WILL INCREASE. HOWEVER, OUR DIRECTORS, EXECUTIVE OFFICERS AND AFFILIATES MAY, IN COMPLIANCE WITH STOCK OWNERSHIP GUIDELINES AND APPLICABLE LAW, SELL THEIR

SHARES IN OPEN MARKET TRANSACTIONS AT PRICES THAT MAY OR MAY NOT BE MORE FAVORABLE THAN THE PURCHASE PRICE TO BE PAID TO OUR SHAREHOLDERS PURSUANT TO THE OFFER. SEE SECTION 11.

In accordance with Rule 13e-4(f)(1) under the Exchange Act, and we expressly reserve the right to, amend the Offer to purchase under the Offer an additional number of securities, up to 2% of the outstanding Shares, without extending the Expiration Date.

Therefore, we may not purchase all of the Shares that you tender even if you tender them at or below the Purchase Price.

The Purchase Price will be paid net to the seller in cash, less any applicable withholding taxes and without interest, for all Shares purchased. Tendering shareholders who hold Shares registered in their own name and who tender their Shares directly to the Depositary will not be obligated to pay brokerage commissions, solicitation fees or stock transfer taxes on the purchase of Shares by us in the Offer. Shareholders holding Shares in a brokerage account or otherwise through brokers, dealers, commercial banks, trust companies or other nominees are urged to consult their brokers or such other nominees to determine whether transaction costs may apply if shareholders tender Shares through such brokers or other nominees and not directly to the Depositary. See Sections 3 and 13 regarding certain tax consequences of the Offer.

Also, any tendering shareholder or other payee who fails to complete, sign and return to the Depositary the Substitute Form W-9 included with the Letter of Transmittal (or such other Internal Revenue Service (“IRS”) form as may be applicable) may be subject to United States federal income tax backup withholding (28% of the gross proceeds in the case of U.S. Holders (as defined in Section 13)), unless such holder establishes that such holder is within the class of persons that is exempt from backup withholding, such as all corporations. See Section 3. Also see Section 13 regarding United States federal income tax consequences of the Offer.

Tendering shareholders whose Shares are registered in their own names and who tender directly to American Stock Transfer & Trust Company, the Depositary for the Offer, will not be obligated to pay brokerage fees or commissions or, except as described in Section 5, stock transfer taxes on the purchase of Shares by us in the Offer. If you own your Shares through a bank, broker, dealer, trust company or other nominee and the

nominee tenders your Shares on your behalf, the nominee may charge you a fee for doing so. You should consult your bank, broker, dealer, trust company or other nominee to determine whether any charges apply.

In addition, holders of vested but unexercised options outstanding under the BancFirst Corporation Stock Option Plan, the Directors’ Stock Plan and the Directors’ Deferred Stock Compensation Plan (collectively, the “Stock Option Plans”) may, subject to the terms and conditions of the applicable Stock Option Plan and the applicable option grant, exercise such options and tender some or all of the Shares issued upon such exercise. See Sections 3 and 11 for more information on the Stock Option Plans generally.

Participants in our equity-based retirement plans whose shares are held by a trustee may not use the Letter of Transmittal to direct the tender of the shares but instead must follow the separate instructions in the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan,” sent separately to each eligible participant in the plans, to tender some or all of the Shares allocated to units they hold in the equity unit funds in their participant accounts. If a participant’s instructions are not received by 5:00 pm, New York City Time, on Tuesday, September 4, or if we extend the Offer, before 5:00 pm, New York City Time, on the expiration date of the Offer, as extended, the trustee will not tender Shares allocated to the participant’s account. See Section 3.

We will pay all fees and expenses incurred in connection with the Offer by MacKenzie Partners, Inc., the Information Agent for the Offer, American Stock Transfer & Trust Company, the Depositary for the Offer, and Friedman, Billings, Ramsey & Co., Inc., the Dealer Manager for the Offer. See Section 16.

As of July 31, 2007, we had 15,724,536 issued and outstanding Shares. The 500,000 Shares that we are offering to purchase pursuant to the Offer represent approximately 3.2% of our Shares outstanding as of July 31, 2007. To the extent any of our shareholders tender their Shares in full and that tender is accepted in full, the number of our record holders would be reduced. See Section 2.

The Shares are listed and traded on the Nasdaq under the symbol “BANF.” On August 1, 2007, the last full trading day before the announcement of the Offer, the last reported sale price of the Shares was $40.59 per Share. Shareholders are urged to obtain current market quotations for the Shares prior to making their decision whether or not to tender pursuant to the Offer. See Section 8.

Upon the terms and subject to the conditions of the Offer, we will purchase up to 500,000 Shares, including the associated preferred stock purchase rights, properly tendered and not properly withdrawn in accordance with Section 4 before the Expiration Date, as defined below, at a Purchase Price not greater than $45.00 and not less than $39.50 per Share, net to the seller in cash, less any applicable withholding taxes and without interest.

The term “Expiration Date” means 5:00 p.m., New York City time, on September 4, 2007. We may, in our sole discretion, extend the period of time during which the Offer will remain open. In the event of an extension, the term “Expiration Date” will refer to the latest time and date at which the Offer, as extended by us, will expire. See Section 15 for a description of our right to extend, delay, terminate or amend the Offer.

If the Offer is over-subscribed as described below, Shares tendered at or below the Purchase Price and not properly withdrawn will be subject to proration, except for Odd Lots. The proration period and, except as described herein, withdrawal rights expire at the Expiration Date.

In accordance with Instruction 4 to the Letter of Transmittal, shareholders desiring to tender Shares must either (i) specify that they are willing to sell their Shares to us at the price determined in the Offer or (ii) specify the price, not greater than $45.00 nor less than $39.50 per Share (in multiples of $0.25), at which they are willing to sell their Shares to us in the Offer. Promptly following the Expiration Date, we will, upon the terms and subject to the conditions of the Offer, determine a single per Share Purchase Price that we will pay for Shares properly tendered and not properly withdrawn pursuant to the Offer, taking into account the number of Shares tendered and the prices at which they are tendered. We will select the lowest purchase price specified by tendering shareholders that will allow us to buy 500,000 Shares or, if a lesser number of Shares is properly tendered, all Shares that are properly tendered and not properly withdrawn. All Shares purchased in the Offer will be purchased at the same Purchase Price. If tendering shareholders wish to maximize the chance that their Shares will be purchased, they should check the box in the section of the Letter of Transmittal captioned “Shares Tendered at a Price Determined Pursuant to the Offer.” Note that this election could result in the tendered Shares being purchased at the minimum price of $39.50 per Share.

In the event the Purchase Price is less than the maximum price of $45.00 per Share and more than 500,000 Shares are tendered in the Offer at or below the Purchase Price, we may exercise our right to amend the Offer to purchase up to an additional 2% of our outstanding Shares without extending the Expiration Date. If we exercise our right to purchase up to an additional 2% of our outstanding Shares, then we could have as few as 14,910,045 Shares outstanding following the purchase of the Shares tendered in the Offer. We also expressly reserve the right, in our sole discretion, to purchase additional Shares subject to applicable legal requirements. See Section 15.

As described in greater detail below, if the Offer is over-subscribed, Shares tendered at or below the Purchase Price will be subject to proration.

Only Shares properly tendered at prices at or below the Purchase Price and not properly withdrawn will be purchased. However, because of the proration and conditional tender provisions of the Offer, all of the Shares tendered at or below the Purchase Price will not be purchased if more than the number of Shares we seek are properly tendered. All Shares tendered and not purchased in the Offer, including Shares tendered at or below the Purchase Price and Shares not purchased because of proration or conditional tenders, will be returned to the tendering shareholders at our expense promptly following the Expiration Date.

If we (i) increase the price that may be paid for the Shares above $45.00 per Share or decrease the price that may be paid for the Shares below $39.50 per Share, (ii) materially increase the Dealer Manager’s fee, (iii) increase the number of Shares that we may purchase in the Offer by more than 2% of our outstanding Shares

or (iv) decrease the number of Shares that we may purchase in the Offer, then the Offer must remain open for at least ten business days following the date that notice of the increase or decrease is first published, sent or given in the manner specified in Section 15.

THE OFFER IS NOT CONDITIONED ON ANY MINIMUM NUMBER OF SHARES BEING TENDERED. OUR OBLIGATION TO ACCEPT AND PAY FOR SHARES VALIDLY TENDERED PURSUANT TO THE OFFER IS, HOWEVER, SUBJECT TO OTHER CONDITIONS. SEE SECTION 7.

Priority of Purchases. If more than 500,000 Shares (or such greater number of Shares as we may elect to purchase subject to applicable law) are properly tendered and not properly withdrawn, we will purchase Shares in the following order of priority:

Therefore, we may not purchase all of the Shares that you tender even if you tender them at or below the Purchase Price.

Odd Lots. The term “Odd Lots” means all Shares tendered by any person (an “Odd Lot Holder”) who owned beneficially or of record an aggregate of fewer than 100 Shares. Odd Lots will be accepted for payment at the same time as other tendered Shares.

Proration. If proration of tendered Shares is required, we will determine the proration factor promptly following the Expiration Date. Proration for each shareholder tendering Shares (excluding Odd Lot Holders) will be based on the ratio of the number of Shares tendered by the shareholder to the total number of Shares tendered by all shareholders (excluding Odd Lot Holders), subject to conditional tenders. Because of the difficulty in determining the number of Shares properly tendered and not properly withdrawn, and because of the conditional tender procedure described in Section 6, we do not expect that we will be able to announce the final proration factor or commence payment for any Shares purchased pursuant to the Offer until approximately three business days after the Expiration Date. The preliminary results of any proration will be announced by press release promptly after the Expiration Date. Shareholders may obtain preliminary proration information from the Information Agent and also may be able to obtain the information from their brokers.

As described in Section 13, the number of Shares that we will purchase from a shareholder pursuant to the Offer may affect the United States federal income tax consequences to the shareholder of the purchase and, therefore, may be relevant to a shareholder’s decision whether or not to tender Shares. The Letter of Transmittal affords each shareholder who tenders Shares registered in such shareholder’s name directly to the Depositary the

opportunity to designate the order of priority in which Shares tendered are to be purchased in the event of proration as well as the ability to condition such tender on a minimum number of Shares being purchased. See Section 6.

This Offer to Purchase and the related Letter of Transmittal will be mailed to record holders of the Shares and will be furnished to brokers, dealers, commercial banks, trust companies or other nominee shareholders and similar persons whose names, or the names of whose nominees, appear on our shareholder list or, if applicable, who are listed as participants in a clearing agency’s security position listing for subsequent transmittal to beneficial owners of Shares.

Purpose of the Offer. We believe that the repurchase of Shares is consistent with our long-term goal of maximizing shareholder value. Our management and Board of Directors have evaluated the Company’s operations, financial condition, capital needs, strategy and expectations for the future and believe that the Offer is a prudent use of our financial resources given our business profile and assets, and that investing in our own Shares is an attractive use of capital and an efficient means to provide liquidity to our shareholders.

The Offer represents the opportunity for us to return cash to shareholders who elect to tender their Shares. Where Shares are tendered by the registered owner of those Shares directly to the Depositary, the sale of those Shares in the Offer will permit the seller to avoid the usual transaction costs associated with open market sales. Furthermore, Odd Lot Holders who hold Shares registered in their names and tender their Shares directly to the Depositary and whose Shares are purchased under the Offer will avoid not only the payment of brokerage commissions but also any applicable odd lot discounts that might be payable on sales of their Shares in Nasdaq transactions.

The Offer represents a mechanism to provide shareholders with the opportunity to tender all or a portion of their Shares and, thereby, receive a return of capital if they so elect. The Offer also provides shareholders (particularly those who, because of the size of their shareholdings, might not otherwise be able to sell their Shares without potential disruption to the market price) with an opportunity to obtain liquidity with respect to all or a portion of their holdings, without potential disruption to the market price and the usual costs associated with open market transactions.

Moreover, our Board of Directors determined to conduct a “modified Dutch auction” tender offer at a price range of $39.50 to $45.00 for the Shares after considering, among other things, recent stock trading ranges and volumes for the Shares, various self tender offers affected by other companies, liquidity opportunities available to our shareholders, and our results of operations, current financial condition and expected future cash needs.

We currently anticipate that we will have adequate cash generating capacity, and we expect that our current cash balances, anticipated cash flows from operations and borrowing capacity will exceed our capital requirements for normal operations, capital expenditures and acquisitions and other opportunities for growth that may arise. However, actual experience may differ significantly from our expectations. See “Cautionary Notice Regarding Forward-Looking Statements.” In considering the Offer, our management and the Board of Directors took into account the expected financial impact of the Offer. See Section 6.

THE RELATED LETTER OF TRANSMITTAL, INCLUDING THE PURPOSES AND EFFECTS OF THE OFFER. YOU SHOULD DISCUSS WHETHER TO TENDER YOUR SHARES WITH YOUR BROKER, IF ANY, OR OTHER FINANCIAL OR TAX ADVISORS.

Potential Benefits of the Offer. We believe the Offer will provide benefits to us and our shareholders, including the following:

Potential Risks and Disadvantages of the Offer. The Offer also presents some potential risks and disadvantages to us and our continuing shareholders, including the following:

As of July 31, 2007, we had 15,724,536 issued and outstanding Shares. The 500,000 Shares that we are offering to purchase pursuant to the Offer, assuming the Offer is fully subscribed, represent approximately 3.2% of the Shares outstanding as of that date. Shareholders may be able to sell non-tendered Shares in the future on the Nasdaq or otherwise, at a net price higher or lower than the purchase price in the Offer. The lower end of the price range for the Offer is below the closing market price for the Shares on the Nasdaq on August 1, 2007, the last full trading day prior to announcement of the Offer. We can give no assurance, however, as to the price at which a shareholder may be able to sell such Shares in the future, which may be higher or lower than the Purchase Price paid by us in the Offer.

Certain Effects of the Offer. Shareholders who do not tender their Shares pursuant to the Offer and shareholders who otherwise retain an equity interest in BancFirst Corporation as a result of a partial tender of Shares, proration or a conditional tender for which the condition is not satisfied will continue to be owners of BancFirst Corporation and will realize a proportionate increase in their relative equity interest in BancFirst Corporation and thus in the Company’s future earnings and assets at no additional cost to them, and will bear the attendant risks and rewards associated with owning the equity securities of BancFirst Corporation, including risks resulting from the Company’s purchase of Shares. We can give no assurance, however, that we will not issue additional Shares or equity interests in the future.

Our book value per share is expected to decrease as a result of the Offer. We believe the Offer, if completed, will be accretive to currently projected earnings per share, although there can be no assurance of this.

Shares we acquire pursuant to the Offer will become authorized and unissued Shares and will be available for us to issue without further shareholder action (except as required by applicable law or the listing standards of the Nasdaq) for purposes including, without limitation, acquisitions, raising additional capital and the satisfaction of obligations under existing or future employee benefit or compensation programs or stock plans or compensation programs for directors.

None of our directors and executive officers intends to tender any of their Shares in the Offer, except for Robert A. Gregory, a director, who intends to tender 3,000 shares, and Mike Rogers, Executive Vice President—Human Resources, who intends to tender 4,000 shares. As a consequence, the beneficial ownership of our directors and executive officers will increase to approximately 48.72% of the total outstanding Shares assuming that the maximum 500,000 Shares are purchased in the Offer. See Section 11.

The Offer also provides certain shareholders with an efficient way to sell their Shares without incurring brokers’ fees or commissions. Where Shares are tendered by the registered owner of those Shares directly to the Depositary, the sale of those Shares in the Offer will permit the seller to avoid the usual transaction costs associated with open market transactions. Furthermore, Odd Lot Holders who hold Shares registered in their names and tender their Shares directly to the Depositary and whose Shares are purchased in the Offer will avoid not only the payment of brokerage commissions but also any applicable Odd Lot discounts that might be payable on sales of their Shares in transactions on the Nasdaq.

The Offer is consistent with our recent history of repurchasing Shares from time to time as a means of increasing shareholder value. In November 1999, our Board of Directors authorized a stock repurchase program (“SRP”) to repurchase up to 600,000 Shares of the Company’s outstanding Common Stock. The SRP was amended in May 2001 to increase the shares authorized to be purchased by 555,832 shares, and was amended again in August 2002 to increase the number of shares authorized to be purchased by 364,530 shares. At July 31, 2007, there were 233,052 Shares remaining that could be repurchased under the SRP.

Whether or to what extent we choose to make additional purchases will depend upon, among other things, market conditions, our capital needs, our business and financial condition, and alternative investment opportunities available to us, and there is no assurance that we will conclude such purchases for all of the authorized amount. These purchases may be made from time to time at the discretion of our management on the open market, in privately negotiated transactions or otherwise, and may be on the same terms or on terms and prices that are more or less favorable to shareholders than the terms of this Offer. However, Rule 13e-4 under the Exchange Act prohibits us and our affiliates from purchasing any Shares, or other securities convertible into Shares, other than pursuant to the Offer, until at least ten business days following the Expiration Date, except pursuant to certain limited exemptions provided in Rule 14e-5 of the Exchange Act. Accordingly, no purchases under the SRP will be made by us during the pendency of the Offer and until at least ten business days following the Expiration Date. See Section 11.

Other Plans. Except as otherwise disclosed in this Offer to Purchase, we currently have no plans, proposals or negotiations underway that relate to or would result in:

Proper Tender of Shares. For Shares to be tendered properly pursuant to the Offer:

(1) the confirmation of receipt of the Shares pursuant to the procedure for book-entry transfer set forth below, together with a properly completed and duly executed Letter of Transmittal, or a manually signed facsimile of the Letter of Transmittal, including any required signature guarantees, or an Agent’s Message (as defined below) in the case of a book-entry transfer, and any other documents required by the Letter of Transmittal, must be received before the Expiration Date by the Depositary at its address set forth on the back cover of this Offer to Purchase; or

(2) the tendering shareholder must comply with the guaranteed delivery procedure set forth below.

In accordance with Instruction 5 to the Letter of Transmittal, each shareholder desiring to tender Shares in the Offer must either (i) check the box in the section of the Letter of Transmittal captioned “Shares Tendered at a Price Determined Pursuant to the Offer,” in which case you will be deemed to have tendered your Shares at the minimum price of $39.50 per Share (YOU SHOULD UNDERSTAND THAT THIS ELECTION MAY LOWER THE PURCHASE PRICE PAID FOR ALL PURCHASED SHARES IN THE OFFER AND COULD RESULT IN THE TENDERED SHARES BEING PURCHASED AT THE MINIMUM PRICE OF $39.50 PER SHARE) or (ii) check one of the boxes in the section of the Letter of Transmittal captioned “Price (in Dollars) per Share at Which Shares are Being Tendered,” indicating the price at which Shares are being tendered. A tender of Shares will be proper if, and only if, one of these boxes is checked on the Letter of Transmittal.

If tendering shareholders wish to maximize the chance that their Shares will be purchased, they should check the box in the section on the Letter of Transmittal captioned “Shares Tendered at a Price Determined Pursuant to the Offer.” Note that this election could result in the tendered Shares being purchased at the minimum price of $39.50 per Share. The lower end of the price range for the Offer is below the closing market price for the Shares on August 1, 2007, the last full trading day prior to the announcement of the Offer.

If tendering shareholders wish to indicate a specific price (in multiples of $0.25) at which their Shares are being tendered, they must check a box under the section captioned “Price (in Dollars) per Share at Which Shares are Being Tendered.” Tendering shareholders should be aware that this election could mean that none of their Shares will be purchased if they check a box other than the box representing the lowest price. A shareholder who wishes to tender Shares at more than one price must complete separate Letters of Transmittal for each price at which Shares are being tendered. The same Shares cannot be tendered (unless previously properly withdrawn in accordance with the terms of the Offer) at more than one price. Separate notices of withdrawal (described in Section 4) are not required for each Letter of Transmittal unless each Letter of Transmittal tenders Shares at different prices; however, absent a notice of withdrawal, subsequent Letters of Transmittal do not revoke prior Letters of Transmittal. Shareholders may contact the Depositary for additional instructions.

Shareholders holding their Shares in a brokerage account or otherwise through a broker, dealer, commercial bank, trust company or other nominee, must contact their brokers or such other nominee in order to tender their Shares. It is likely that the nominee has established an earlier deadline for you to act to instruct the nominee to accept the Offer on your behalf. Shareholders who hold Shares through nominee shareholders are urged to consult their nominees to determine whether transaction costs may apply if shareholders tender Shares through the nominees and not directly to the Depositary.

Participants in our equity-based retirement plans whose Shares are held by a trustee may not use the Letter of Transmittal to direct the tender of Shares allocated to units they hold in the equity unit funds in their accounts under the plans but instead must follow the instructions in the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” sent separately to each eligible participant in the plans. These instructions require that a plan participant who wishes to tender shares under the plan complete the Direction Form as directed in the letter. The deadline for submitting Direction Forms will be 5:00 p.m., New York City time, on Tuesday, September 4, 2007, unless we extend the Offer, in which case you may submit your Direction Form until 5:00 pm, New York City time, on the expiration date of the Offer, as extended.

Participants in these two retirement plans should be aware that the plans are prohibited from selling shares to us for a price less than the prevailing market price. Accordingly, if you elect to tender Shares allocated to units you hold in the equity funds under either of these plans, and the last-sale-eligible-trade price of our Common Stock on Nasdaq on September 4, 2007 is more than the price at which you tendered Shares, your Shares will not be eligible for the Offer, and your tender of plan Shares automatically will be withdrawn.

The proceeds received by our retirement plan from any tender of plan Shares will remain in the respective retirement plan and may be withdrawn only in accordance with the terms of the plan. All documents furnished to stockholders generally in connection with the Offer will be made available to our retirement plan participants. Our retirement plan participants are urged to read the separate “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” and related materials carefully. Such letters and Section 13 of this Offer to Purchase contain additional information regarding the tax rules that will apply with respect to Shares tendered from a participant’s plan account.

The valid tender of Shares by you through one of the procedures described in this Section 3 will constitute a binding agreement between you and us on the terms of, and subject to the conditions to, the Offer.

Shareholders may tender Shares subject to the condition that a specified minimum number of Shares (including all) or none be purchased. Any shareholder desiring to make such a conditional tender should so indicate in the box captioned “Conditional Tender” on the Letter of Transmittal and, if applicable, on the Notice of Guaranteed Delivery. It is the tendering shareholder’s responsibility to determine the minimum number of Shares to be purchased. SHAREHOLDERS SHOULD CONSULT THEIR INVESTMENT AND TAX ADVISORS WITH RESPECT TO THE EFFECT OF PRORATION OF THE OFFER AND THE ADVISABILITY OF MAKING A CONDITIONAL TENDER. See Section 13.

Signature Guarantees and Method of Delivery. No signature guarantee is required if:

(1) the Letter of Transmittal is signed by the registered holder of the Shares (which term, for purposes of this Section 3, will include any participant in The Depository Trust Company (“DTC”) whose name appears on a security position listing as the owner of the Shares) tendered and the holder has not completed either the box entitled “Special Mailing Instructions” or the box entitled “Special Transfer Instructions” on the Letter of Transmittal; or

(2) Shares are tendered for the account of a bank, broker, dealer, credit union, savings association or other entity which is a member in good standing of the Securities Transfer Agents Medallion Program or an

“eligible guarantor institution,” as the term is defined in Rule 17Ad-15 under the Exchange Act (each of the foregoing constituting an “Eligible Institution”).

A “registered holder” of tendered Shares will include any participant in the DTC’s system whose name appears on a security position listing as the owner of those Shares, and an “eligible institution” is a “financial institution,” which term includes most commercial banks, savings and loan associations and brokerage houses, that are participants in any of the following: (i) the Securities Transfer Agents Medallion Program; (ii) The New York Stock Exchange, Inc. Medallion Signature Program; or (iii) the Stock Exchange Medallion Program.

Except as described above, all signatures on any Letter of Transmittal for Shares tendered thereby must be guaranteed by an eligible institution. See Instructions 1 and 6 to the Letter of Transmittal. If the certificates for Shares are registered in the name of a person other than the signer of the Letter of Transmittal, or if payment is to be made or certificates for Shares not tendered or not accepted for payment are to be returned to a person other than the registered holder of the certificates surrendered, then the tendered certificates must be endorsed or accompanied by appropriate stock powers, in either case signed exactly as the name or names of the registered holders or owners appear on the certificates, with the signatures on the certificates or stock powers guaranteed by an eligible institution. See Instructions 1 and 6 to the Letter of Transmittal.

If a book-entry account system is registered in the name of a person other than the person executing a Letter of Transmittal, or if payment is to be made, or Shares not purchased or tendered are to be returned, to a person other than the registered holder, then the book-entry account system must be endorsed or accompanied by an appropriate stock power, signed in either case exactly as the name of the registered holder appears on the book-entry account system, with the signature guaranteed by an Eligible Institution.

In all cases, payment for Shares tendered and accepted for payment pursuant to the Offer will be made only after timely receipt by the Depositary of a properly completed and duly executed Letter of Transmittal, or a facsimile thereof, including any required signature guarantees, or an Agent’s Message (as defined below) in the case of a book-entry transfer, and any other documents required by the Letter of Transmittal.

Shareholders also can specify the order in which we will purchase the specified portions in the event that, as a result of the proration provisions or otherwise, we purchase some but not all of the tendered Shares pursuant to the Offer. In the event the shareholder does not designate the order and fewer than all Shares are purchased due to proration, the Depositary will select the order of Shares purchased.

Odd Lot Holders who tender all of their Shares must also complete the section captioned “Odd Lots” in the Letter of Transmittal and, if applicable, in the Notice of Guaranteed Delivery, to qualify for the priority treatment available to Odd Lot Holders as set forth in Section 1.

The method of delivery of all documents, including the Letter of Transmittal and any other required documents, including through the DTC, is at the election and risk of the tendering shareholder. Shares will be deemed delivered only when actually received by the Depositary (including, in the case of a book-entry transfer, by book-entry confirmation). If delivery is by mail, then registered mail with return receipt requested, properly insured, is recommended. In all cases, sufficient time should be allowed to ensure timely delivery.

Book-Entry Delivery. For purposes of the Offer, the Depositary will establish an account with respect to the Shares for purposes of the Offer at DTC within two business days after the date of this Offer to Purchase, and any financial institution that is a participant in DTC’s system may make book-entry delivery of the Shares by causing DTC to transfer Shares into the Depositary’s account in accordance with DTC’s procedures for transfer. Although delivery of Shares may be effected through a book-entry transfer into the Depositary’s account at DTC, either (i) a properly completed and duly executed Letter of Transmittal, or facsimile thereof, with any required signature guarantees, or an Agent’s Message, and any other required documents must be transmitted to and received by the Depositary at one of its addresses set forth on the back cover of this Offer to Purchase before the

Expiration Date, or (ii) the guaranteed delivery procedure described below must be followed. Delivery of the Letter of Transmittal and any other required documents to DTC does not constitute delivery to the Depositary.

The term “Agent’s Message” means a message transmitted by DTC to, and received by, the Depositary and forming a part of a book-entry confirmation, which states that DTC has received an express acknowledgement from the DTC participant tendering Shares that such DTC participant has received and agrees to be bound by the terms of the Letter of Transmittal and that BancFirst Corporation may enforce such agreement against the DTC participant.

Guaranteed Delivery. If a shareholder desires to tender Shares pursuant to the Offer and the procedure for book-entry transfer cannot be completed before the Expiration Date, or if time will not permit all required documents to reach the Depositary before the Expiration Date, the Shares still may be tendered, if all of the following conditions are satisfied:

(2) the Depositary receives by mail, overnight courier, or facsimile transmission, on or before the Expiration Date, a properly completed and duly executed Notice of Guaranteed Delivery substantially in the form BancFirst Corporation has provided with this Offer to Purchase, including (where required) a signature guarantee by an Eligible Institution in the form set forth in the Notice of Guaranteed Delivery; and

(3) the confirmation of book-entry transfer of the Shares into the Depositary’s account at DTC, together with a properly completed and duly executed Letter of Transmittal, or a facsimile thereof, or an Agent’s Message in the case of a book-entry transfer, and any required signature guarantees and other documents required by the Letter of Transmittal, are received by the Depositary within three business days after the date of receipt by the Depositary of the Notice of Guaranteed Delivery.

If tendering shareholders wish to maximize the chance that their Shares will be purchased by us, they should check the box in the section of the Letter of Transmittal captioned “Shares Tendered at a Price Determined Pursuant to the Offer.” Note that this election could result in tendered Shares being purchased at the minimum price of $39.50 per Share. See Section 3.

Shareholders may contact the Information Agent, the Dealer Manager or their broker for assistance. The contact information for the Information Agent and the Dealer Manager is on the back cover page of this Offer to Purchase.

Stock Option Plans; Stock Awards. Holders of vested but unexercised options may exercise such options in accordance with the terms of the applicable Stock Option Plan and tender the Shares received upon such exercise in accordance with the Offer. See “Proper Tender of Shares” above. Holders of vested but unexercised options should evaluate this Offer to Purchase carefully to determine if participation would be advantageous to them, based on their stock option exercise prices, the date of their stock option grants, the years left to exercise their options, the range of tender prices and the provisions for pro rata purchases by us described in Section 1. We strongly encourage those holders to discuss the Offer with their tax advisor, broker and/or financial advisor. Holders of stock awards may not tender Shares or Shares represented by such interests unless they are fully vested.

Return of Unpurchased Shares. If any tendered Shares are not purchased, or if less than all Shares evidenced by a shareholder’s book-entry account are tendered, the Shares not purchased will be credited to the appropriate account maintained by the tendering shareholder at DTC, in each case without expense to the shareholder.

United States Federal Income Tax Withholding and Backup Withholding. Under the United States federal income tax backup withholding rules, 28% of the gross proceeds payable to a shareholder or other payee

pursuant to the Offer must be withheld and remitted to the United States Treasury, unless the shareholder or other payee provides his or her taxpayer identification number (employer identification number or social security number) to the Depositary and certifies that such number is correct or an exemption otherwise applies under applicable regulations. Therefore, unless an exemption exists and is proven in a manner satisfactory to the Depositary, each tendering shareholder should complete and sign the Substitute Form W-9 included as part of the Letter of Transmittal so as to provide the information and certification necessary to avoid backup withholding. Certain shareholders (including, among others, all corporations and certain foreign individuals) are not subject to these backup withholding and reporting requirements. In order for a foreign individual to qualify as an exempt recipient, that shareholder must submit a statement (generally, an IRS Form W-8BEN), signed under penalties of perjury, attesting to that individual’s exempt status. Such statements can be obtained from the Depositary. See “Substitute Form W-9” in the Letter of Transmittal.

ANY TENDERING SHAREHOLDER OR OTHER PAYEE WHO FAILS TO COMPLETE FULLY AND SIGN THE SUBSTITUTE FORM W-9 INCLUDED IN THE LETTER OF TRANSMITTAL MAY BE SUBJECT TO REQUIRED UNITED STATES FEDERAL INCOME TAX BACKUP WITHHOLDING OF 28% OF THE GROSS PROCEEDS PAID TO SUCH SHAREHOLDER OR OTHER PAYEE PURSUANT TO THE TENDER OFFER.

Gross proceeds payable pursuant to the Offer to a foreign shareholder (as defined in Section 13) or his or her agent will be subject to withholding of United States federal income tax at a rate of 30%, unless we determine that a reduced rate of withholding is applicable pursuant to a tax treaty or that an exemption from withholding is applicable because such gross proceeds are effectively connected with the conduct of a trade or business within the United States. A foreign shareholder may be eligible to file for a refund of such tax or a portion of such tax withheld if such shareholder meets the “complete redemption,” “substantially disproportionate” or “not essentially equivalent to a dividend” tests described in Section 13 or if such shareholder is entitled to a reduced rate of withholding pursuant to a tax treaty and we withheld at a higher rate. In order to obtain a reduced rate of withholding under a tax treaty, a foreign shareholder must deliver to the Depositary before the payment a properly completed and executed IRS Form W-8BEN claiming such an exemption or reduction. Such forms can be obtained from the Depositary. In order to claim an exemption from withholding on the grounds that gross proceeds paid pursuant to the Offer are effectively connected with the conduct of a trade or business within the United States, a foreign shareholder must deliver to the Depositary a properly executed IRS Form W-8ECI claiming such exemption. Such forms can be obtained from the Depositary. See “Substitute Form W-9” in the Letter of Transmittal. Backup withholding generally will not apply to amounts subject to the 30% or a treaty-reduced rate of withholding. Foreign shareholders are urged to consult their own tax advisors regarding the application of United States federal income tax withholding, including eligibility for a withholding tax reduction or exemption and the refund procedure.

Tax Withholding for Participants in our Retirement Plans. No withholding tax will be applied with respect to shares tendered through our retirement plans. Please refer to the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” for a discussion of the tax rules applicable to participants in the two plans.

Determination of Validity; Rejection of Shares; Waiver of Defects; No Obligation to Give Notice of Defects. All questions as to the number of Shares to be accepted, the price to be paid for Shares to be accepted and the validity, form, eligibility (including time of receipt) and acceptance for payment of any tender of Shares will be determined by us, in our sole discretion, and our determination will be final and binding on all persons participating in the Offer, except as otherwise determined in a subsequent judicial proceeding or as required by law. We reserve the absolute right prior to the expiration of the Offer to reject any or all tenders of any Shares that we determine are not in proper form or the acceptance for payment of or payment for which may, in the opinion of our counsel, be unlawful. We also reserve the absolute right, subject to applicable law, to waive any of the conditions of the Offer prior to the Expiration Date with respect to all tendered Shares and our interpretation of the terms of the Offer will be final and binding on all persons participating in the Offer, except as otherwise

determined in a subsequent judicial proceeding or as required by law. We also reserve the absolute right to waive any defect or irregularity in any tender with respect to any particular Shares. No tender of Shares will be deemed to have been properly made until all defects or irregularities have been cured by the tendering shareholder or waived by us. We will not be liable for failure to waive any condition of the Offer, or any defect or irregularity in any tender of Shares. None of us, the Depositary, the Information Agent, the Dealer Manager or any other person will be obligated to give notice of any defects or irregularities in tenders, nor will any of them incur any liability for failure to give any notice. Our interpretations of the terms of and conditions to the Offer, including the Letter of Transmittal and the instructions thereto, will be final and binding on all persons participating in the Offer, except as otherwise determined in a subsequent judicial proceeding or as required by law.

Tendering Shareholder’s Representation and Warranty; Acceptance by BancFirst Corporation Constitutes an Agreement. A tender of Shares pursuant to any of the procedures described above will constitute the tendering shareholder’s acceptance of the terms and conditions of the Offer, as well as the tendering shareholder’s representation and warranty to us that (i) the shareholder has a “net long position,” within the meaning of Rule 14e-4 under the Exchange Act, in the Shares or equivalent securities at least equal to the Shares being tendered, and (ii) the tender of Shares complies with Rule 14e-4. It is a violation of Rule 14e-4 for a person, directly or indirectly, to tender Shares for that person’s own account unless, at the time of tender and at the end of the proration period or period during which Shares are accepted by lot (including any extensions thereof), the person so tendering (i) has a net long position equal to or greater than the amount of (a) Shares tendered or (b) other securities convertible into or exchangeable or exercisable for the Shares tendered and will acquire the Shares for tender by conversion, exchange or exercise and (ii) will deliver or cause to be delivered the Shares in accordance with the terms of the Offer. Rule 14e-4 provides a similar restriction applicable to the tender or guarantee of a tender on behalf of another person. Our acceptance for payment of Shares tendered pursuant to the Offer will constitute a binding agreement between the tendering shareholder and us upon the terms and conditions of the Offer.

A properly completed Letter of Transmittal and any other documents required by the Letter of Transmittal, must be delivered to the Depositary and not to us, the Dealer Manager or the Information Agent.

Lost Certificates. If the share certificates which a registered holder wants to surrender have been lost, destroyed or stolen, the shareholder should follow the instructions set forth in the Letter of Transmittal. See Instruction 14 of the Letter of Transmittal.

WE WILL DECIDE, IN OUR REASONABLE DISCRETION, ALL QUESTIONS AS TO THE NUMBER OF SHARES TO BE ACCEPTED, THE PRICE TO BE PAID FOR SHARES TO BE ACCEPTED AND THE VALIDITY, FORM, ELIGIBILITY (INCLUDING TIME OF RECEIPT) AND ACCEPTANCE FOR PAYMENT OF ANY TENDER OF SHARES, AND EACH SUCH DECISION WILL BE FINAL AND BINDING ON ALL PERSONS PARTICIPATING IN THE OFFER, EXCEPT AS OTHERWISE DETERMINED IN A SUBSEQUENT JUDICIAL PROCEEDING OR AS REQUIRED BY LAW.

CERTIFICATES FOR SHARES, TOGETHER WITH A PROPERLY COMPLETED AND DULY EXECUTED LETTER OF TRANSMITTAL OR FACSIMILE THEREOF, OR AN AGENT’S MESSAGE, AND ANY OTHER DOCUMENTS REQUIRED BY THE LETTER OF TRANSMITTAL, MUST BE DELIVERED TO THE DEPOSITARY AND NOT TO US, THE DEALER MANAGER OR THE INFORMATION AGENT. ANY SUCH DOCUMENTS DELIVERED TO US, THE DEALER MANAGER OR THE INFORMATION AGENT WILL NOT BE FORWARDED TO THE DEPOSITARY AND THEREFORE WILL NOT BE DEEMED TO BE PROPERLY TENDERED.

Shares tendered pursuant to the Offer may be withdrawn at any time before the Expiration Date. In addition, unless we have already accepted your tendered Shares for payment, you may withdraw your tendered Shares at any time after 11:59 p.m., New York City time, October 1, 2007. Except as otherwise provided in this Section 4, tenders of Shares pursuant to the Offer are irrevocable.

If we extend the period of time during which the Offer is open, are delayed in accepting for payment or paying for Shares or are unable to accept for payment or pay for Shares pursuant to the Offer for any reason, then, without prejudice to our rights under the Offer, the Depositary may, on our behalf, retain all Shares tendered, and such Shares may not be withdrawn except as otherwise provided in this Section 4, subject to Rule 13e-4(f)(5) under the Exchange Act, which provides that the issuer making the Offer shall either pay the consideration offered, or return the tendered securities, promptly after the termination or withdrawal of the Offer.

For a withdrawal to be effective, a notice of withdrawal must be in written or facsimile transmission form and must be received in a timely manner by the Depositary at one of its addresses set forth on the back cover of this Offer to Purchase and specify the name of the person having tendered the Shares to be withdrawn, the number of Shares to be withdrawn and the name of the registered holder of the Shares to be withdrawn, if different from the name of the person who tendered the Shares.

A shareholder who has tendered Shares at more than one price must complete a separate notice of withdrawal for Shares tendered at each price, so long as the information specified above is included. If Shares have been tendered pursuant to the procedure for book-entry transfer described in Section 3, the notice of withdrawal also must specify the name and the number of the account at DTC to be credited with the withdrawn Shares and must otherwise comply with DTC’s procedures.

All questions as to the form and validity, including the time of receipt, of any notice of withdrawal will be determined by us, in our sole discretion, which determination will be final and binding on all persons participating in the Offer, except as otherwise determined in a subsequent judicial proceeding or as required by law. We also reserve the absolute right to waive any defect or irregularity in the withdrawal of Shares by any shareholder. However, if we waive any defect or irregularity in any withdrawal with respect to any shareholder, we also waive such defect or irregularity with respect to all shareholders. None of us, the Depositary, the Dealer Manager, the Information Agent or any other person will be obligated to give notice of any defects or irregularities in any notice of withdrawal, nor will any of them incur liability for failure to give any notice.

Withdrawals may not be rescinded, and any Shares properly withdrawn will be deemed not properly tendered for purposes of the Offer. However, withdrawn Shares may be re-tendered before the Expiration Date by again following one of the procedures described in Section 3.

Participants in our retirement plans who wish to withdraw their Shares must follow the instructions found in the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” sent separately to each eligible participant in the plans. The deadline for submitting Direction Forms will be 5:00 pm, New York City time, on Tuesday, September 4, 2007, unless we extend the Offer, in which case you may submit your Direction Form until 5:00 pm, New York City time, on the expiration date of the Offer, as extended. See Section 3. Participants in these two retirement plans should be aware that the plans are prohibited from selling shares to us for a price less than the prevailing market price. Accordingly, if you elect to tender Shares allocated to units you hold in the equity funds under either of these plans, and the last-sale-eligible-trade price of our Common Stock on Nasdaq on September 4, 2007 is more than the price at which you tendered Shares, your Shares will not be eligible for the Offer, and your tender of plan Shares automatically will be withdrawn.

Upon the terms and subject to the conditions of the Offer, promptly following the Expiration Date, we (i) will determine which shareholders tendered Shares at or below the Purchase Price and (ii) will accept for payment and pay for (and thereby purchase) up to 500,000 Shares (or such greater number of Shares as we may elect to purchase, subject to applicable law) which are properly tendered at prices at or below the Purchase Price and not properly withdrawn on or before the Expiration Date. For purposes of the Offer, we will be deemed to have accepted for payment (and therefore purchased), subject to the Odd Lot priority, proration and conditional tender provisions of the Offer, Shares that are properly tendered and not properly withdrawn only when, as and if we give oral or written notice to the Depositary of our acceptance of the Shares for payment in the Offer.

Upon the terms and subject to the conditions of the Offer, we will accept for payment and pay the Purchase Price for all such Shares promptly after the Expiration Date. In all cases, payment for Shares tendered and accepted for payment in the Offer will be made promptly, subject to the possible delay in the event of proration, but only after timely receipt by the Depositary of certificates for Shares, book-entry confirmation of Shares into the Depositary’s account at the DTC, and a properly completed and duly executed Letter of Transmittal (or facsimile thereof), an Agent’s Message, in the case of a book-entry transfer, and any other required documents.

We will pay for Shares purchased in the Offer by depositing the aggregate Purchase Price for the Shares with the Depositary, which will act as agent for tendering shareholders for the purpose of receiving payment from us and transmitting payment to the tendering shareholders.

In the event of proration, we will determine the proration factor and pay for those tendered Shares accepted for payment promptly after the Expiration Date. However, we do not expect to be able to announce the final results of any proration and commence payment for Shares purchased until approximately three business days after the Expiration Date. Unless a shareholder specified otherwise in the Letter of Transmittal, certificates for all Shares tendered and not purchased, including Shares tendered at prices in excess of the Purchase Price and Shares not purchased due to proration or conditional tender, will be returned. Shares tendered by book-entry transfer will be credited to the account maintained with the DTC by the participant who delivered the Shares, to the tendering shareholder at our expense promptly after the Expiration Date or termination of the Offer without expense to the tendering shareholders. Under no circumstances will we pay interest on the Purchase Price for any reason, including but not limited to, by reason of any delay in making payment. In addition, if certain events occur, we may not be obligated to purchase Shares in the Offer. See Section 7.

We will pay all stock transfer taxes, if any, payable on the transfer to us of Shares purchased pursuant to the Offer. If, however, payment of the Purchase Price is to be made to, or (in the circumstances permitted by the Offer) unpurchased Shares are to be registered in the name of, any person other than the registered holder, or if tendered book-entry accounts are registered in the name of any person other than the person signing the Letter of Transmittal, the amount of all stock transfer taxes, if any (whether imposed on the registered holder or the other person), payable on account of the transfer to the person will be deducted from the Purchase Price unless satisfactory evidence of the payment of the stock transfer taxes, or exemption from payment of the stock transfer taxes, is submitted.

Any tendering shareholder or other payee who fails to complete fully, sign and return to the Depositary the Substitute Form W-9 included with the Letter of Transmittal (and an IRS Form W-8BEN or other applicable form, if the tendering shareholder or other payee is a Non-U.S. Holder), may be subject to required United States federal income tax backup withholding of 28% of the gross proceeds paid to the shareholder or other payee pursuant to the Offer. See Section 3. Non-U.S. Holders are urged to consult their tax advisors regarding the application of United States federal income tax withholding, including eligibility for a withholding tax reduction or exemption, and the refund procedure.

Under certain circumstances described in Section 1, if the Offer is over-subscribed, Shares will be subject to proration. As discussed in Section 13, the number of Shares to be purchased from a particular shareholder may affect the tax treatment of the purchase to the shareholder and the shareholder’s decision whether to tender. Accordingly, a shareholder may tender Shares subject to the condition that a specified minimum number of the shareholder’s Shares tendered pursuant to a Letter of Transmittal or Notice of Guaranteed Delivery must be purchased if any Shares tendered are purchased. Any shareholder desiring to make a conditional tender must so indicate in the box captioned “Conditional Tender” in the Letter of Transmittal or, if applicable, the Notice of Guaranteed Delivery. Each shareholder is urged to consult with his or her own tax advisor with respect to his or her particular situation.

Any tendering shareholder wishing to make a conditional tender must calculate and appropriately indicate the number of Shares that must be purchased if any are to be purchased. After the Expiration Date, if more than 500,000 Shares (or such greater number of Shares as we may elect to purchase, subject to applicable law) are properly tendered and not properly withdrawn, so that we must prorate our acceptance of and payment for tendered Shares, we will calculate a preliminary proration percentage based upon all Shares properly tendered, conditionally or unconditionally, and not properly withdrawn (including Shares of Odd Lot Holders). If the effect of this preliminary proration would be to reduce the number of Shares to be purchased from any shareholder tendered pursuant to a Letter of Transmittal below the minimum number specified, the Shares conditionally tendered will automatically be regarded as withdrawn (except as provided in the next paragraph). All Shares tendered by a shareholder subject to a conditional tender and that are withdrawn as a result of proration will be returned at our expense to the tendering shareholder promptly after the Expiration Date.

After giving effect to these withdrawals, we will accept the remaining Shares properly tendered, conditionally or unconditionally, on a pro rata basis, if necessary. If conditional tenders that would otherwise be regarded as withdrawn would cause the total number of Shares to be purchased to fall below 500,000 (or such greater number of Shares as we may elect to purchase, subject to applicable law) then, to the extent feasible, we will select enough of the Shares conditionally tendered that would otherwise have been withdrawn to permit us to purchase such number of Shares. In selecting among the conditional tenders, we will select by random lot, treating all tenders by a particular taxpayer as a single lot, and will limit our purchase in each case to the designated minimum number of Shares to be purchased. To be eligible for purchase by random lot, shareholders whose Shares are conditionally tendered must have tendered all of their Shares.

Notwithstanding any other provision of the Offer, we will not be required to accept for payment, purchase or pay for any Shares tendered, and may terminate or amend the Offer or may postpone the acceptance for payment of, or the purchase of and the payment for Shares tendered, subject to Rule 13e-4(f) under the Exchange Act, if at any time on or after the commencement of the Offer and before the Expiration Date any of the following events have occurred (or shall have been reasonably determined by us to have occurred):

As used in this Offer to Purchase, the phrase “the benefits of the Offer” or similar words refer to the efficient deployment of capital in a transaction expected to be accretive to earnings per share without, in the Company’s reasonable judgment, creating a meaningful negative effect on the Company’s liquidity and ability to fund future operations as well as the other benefits described in Section 2. In addition, as used in this Offer to Purchase, the phrase “the contemplated future conduct of our business” or similar words refer to the continuation of the Company’s business in substantially the same manner as currently conducted with the preservation or improvement of relationships with important employees, consultants, customers, suppliers and others doing business with us; the preservation or improvement of our financial performance, cash flow, assets and capital resources; and the avoidance of any significant contingent or realized liabilities outside of those incurred in the ordinary course of our business substantially as currently conducted.

The foregoing addresses the only conditions under which we are not obligated to complete the Offer. The conditions referred to above are for our sole benefit and may be asserted by us regardless of the circumstances (other than any action or omission to act by us) giving rise to any condition, and may be waived by us, in whole or in part, at any time and from time to time in our reasonable discretion prior to the Expiration Date. Our failure at any time to exercise any of the foregoing rights will not be deemed a waiver of any right, and each such right will be deemed an ongoing right that may be asserted at any time prior to the Expiration Date and from time to time. However, once the Offer has expired, then all of the conditions to the Offer, other than those requiring receipt of necessary governmental approvals, must have been satisfied or waived. In certain circumstances, if we waive any of the conditions described above, we may be required to extend the Expiration Date. Any determination by us concerning the events described above will be final and binding on all persons participating in the Offer, except as otherwise determined in a subsequent judicial proceeding or as required by law. Our right to terminate or amend the Offer or to postpone the acceptance for payment of, or the purchase of and the payment for Shares tendered if any of the above listed events occur (or shall have been reasonably determined by us to have occurred) at any time prior to the Expiration Date shall not be affected by any subsequent event regardless of whether such subsequent event would have otherwise resulted in the event having been “cured” or ceasing to exist.

Our Common Stock is listed for trading on the Nasdaq. Our Common Stock trades on the Nasdaq under the symbol “BANF.” The following table sets forth, for the period indicated, the high and low sales prices per share for our Common Stock as reported on the Nasdaq.

On August 1, 2007, the last full trading day before the announcement of the Offer, the last reported sale price of the Shares as reported on the Nasdaq was $40.59. We urge shareholders to obtain a current market quotation for the Shares before deciding whether and at what price or prices to tender their Shares.

Rights Agreement. We adopted the Rights Agreement on February 25, 1999. Under the Rights Agreement one right was issued and attached to each share of our Common Stock including all Shares that were outstanding. Each right entitles the holder, in the circumstances described below, to purchase from us a unit consisting of one one-hundredth of a share of Series A Preferred Stock, par value $.01 per share, of the Company (the “Preferred Stock”) at a purchase price of $110 (the “Exercise Price”), subject to adjustment in certain events.

The rights are attached to all certificates representing outstanding shares of Common Stock and are transferred with and only with these certificates. The rights are exercisable and separately certificated only upon the distribution date, which will occur upon the earlier of the following:

As soon as practicable after the distribution date, certificates will be mailed to holders of record of Common Stock as of the close of business on the distribution date. From and after the distribution date, the separate certificates alone will represent the rights. Prior to the distribution date, all shares of Common Stock issued will be issued with rights. Shares of Common Stock issued after the distribution date will not be issued with rights, except that rights may be issued with Shares of Common Stock issued pursuant to any of:

The final expiration date of the rights will be the close of business on February 25, 2009, unless earlier redeemed or exchanged by us as described below.

In the event that a person acquires 15% or more of the shares of Common Stock then outstanding, except pursuant to a tender offer or exchange offer for all the outstanding shares of our Common Stock approved by our Board of Directors before the person acquires 15% or more of the shares of Common Stock then outstanding, each holder of a right other than that person and certain related parties, whose rights will automatically become null and void, will thereafter be entitled to receive, upon payment of the Exercise Price, a number of shares of Common Stock, or, in certain circumstances, cash, property or other securities of our company, having a market value at the time of the transaction equal to twice the Exercise Price.

If, at any time on or after a person acquires 15% or more of the shares of Common Stock then outstanding, our company effects a merger or other business combination in which it is not the surviving entity, or any shares of our Common Stock are changed into or exchanged for other securities, or 50% or more of its assets, cash flow or earning power is sold or transferred, then each holder of a right, except rights owned by any person who has acquired 15% or more of the shares of Common Stock then outstanding or certain related parties, which will have become void as set forth above, will thereafter have the right to receive, upon exercise, a number of shares of Common Stock of the acquiring company having a fair market value equal to two times the exercise price of the right.

The exercise price payable, and the number of shares of Preferred Stock, shares of Common Stock or other securities or property issuable, upon exercise of the rights are subject to adjustment from time to time to prevent dilution in the event of a stock dividend on the Preferred Stock or Common Stock, a subdivision or combination of the Preferred Stock or Common Stock, a grant or distribution to holders of the Preferred Stock of certain subscription rights, warrants, evidence of indebtedness, cash or other assets, or other similar events.

No fractional rights or shares of Preferred Stock will be issued. In lieu thereof, an adjustment in cash will be made based on the market price of the Common Stock, right or Preferred Stock on the last trading date prior to

the date of exercise. Pursuant to the rights agreement, we reserve the right to require that, prior to the occurrence of one of the events that triggers the ability to exercise the rights, upon any exercise of rights, a number of rights be exercised so that only whole shares of Preferred Stock will be issued.

We will also have the option, at any time after a person acquires 15% and before a person acquires a majority of the shares of our Common Stock then outstanding, to exchange some or all of the rights, other than rights owned by the acquiring person or certain related parties, which will have become void, at an exchange ratio of one share of Common Stock and/or other equity securities deemed to have the same value as one share of Common Stock, per right, subject to adjustment.

At any time prior to the time the rights become exercisable, our Company, by vote of a majority of our Board of Directors, may redeem the rights in whole, but not in part, at a price of $0.01 per right. Upon redemption, the rights will terminate and holders of rights will receive only the redemption price.

For as long as the rights are redeemable, we may amend the rights agreement in any manner, including extending the time period in which the rights may be redeemed. After the time the rights cease to be redeemable, we may amend the rights in any manner that does not materially adversely affect the interests of holders of the rights as such. Until a right is exercised, the holder, as such, will have no rights as a shareholder of our Company, including the right to vote or to receive dividends.

Our certificate of incorporation provides that each share of Preferred Stock that may be issued upon exercise of the rights will be entitled to receive, when, as and if declared, cash and non-cash dividends equal to the greater of:

Each share of Preferred Stock shall entitle the holder thereof to one vote on all matters submitted to a vote of the shareholders of the Company and, except as otherwise provided by the certificate of incorporation, or applicable law, will vote together with holders of Common Stock as a single class. In the event that the preferential quarterly cash dividends are in arrears, holders of Preferred Stock will have the right to elect two additional members of our Board of Directors.

Upon any voluntary or involuntary liquidation, dissolution or winding up of the Company, no distributions may be made (i) to the holders of shares of junior stock unless the holders of Preferred Stock shall have received the greater of either (a) $100.00 per share plus an amount equal to accrued and unpaid dividends and distributions thereon, whether or not declared, to the date of such payment, or (b) an amount per share equal to 100 times the aggregate per share amount to be distributed to holders of shares of Common Stock or (ii) to the holders of shares of parity stock, unless simultaneously therewith distributions are made ratably on shares of the Preferred Stock and all other shares of such parity stock.

The rights of the Preferred Stock as to dividends, voting and liquidation are protected by antidilution provisions. In the event of a consolidation, merger or other transaction in which the shares of capital stock are exchanged, holders of shares of Preferred Stock will be entitled to receive an amount per share, equal to 100 times the amount of stock, securities, cash or other property for which each share of Common Stock is exchanged. The shares of Preferred Stock are not redeemable at the option of our company or any holder thereof.

The rights have certain anti-takeover effects. The rights cause substantial dilution to any person or group that attempts to acquire our company without the approval of our board. As a result, the overall effect of the

rights may be to render more difficult or discourage any attempt to acquire our company, even if that acquisition may be in the best interests of our shareholders. Because our board can redeem the rights or approve a permitted offer, the rights do not interfere with a merger or other business combination approved by our board.

Even if they have acquired, or obtained the right to acquire, beneficial ownership of 15% or more of the outstanding shares of Common Stock of the Company, each of the following persons (an “Exempt Person”) will not be deemed to be an Acquiring Person: (i) the Company, any subsidiary of the Company, any employee benefit plan or employee stock plan of the Company or any subsidiary of the Company; (ii) any person who becomes an Acquiring Person solely by virtue of a reduction in the number of outstanding shares of Common Stock, unless and until such person shall become the beneficial owner of, or make a tender offer for any additional shares of Common Stock; and (iii) any individual, corporation, partnership or other person, entity or group which “beneficially owned” on February 25, 1999, 15% or more of the outstanding Common Stock of the Company.

The foregoing description of the Rights Agreement is qualified in its entirety by reference to the following documents:

You may obtain copies of the documents referred to in the preceding sentence in the manner provided in Section 10.

Assuming that the maximum number of Shares is tendered in the Offer and the Purchase Price is an amount between $39.50 and $45.00 per share, the aggregate purchase price for the Shares will be between $19,750,000 and $22,500,000.

We will pay for the Shares purchased in the Offer, and the related fees and expenses, from our cash reserves as well as dividend payments from our wholly owned bank subsidiary, BancFirst.

General. The Company, with $3.6 billion in assets at June 30, 2007, is a publicly held financial services holding company incorporated under the laws of the State of Oklahoma in 1984. As a bank holding company registered under the Bank Holding Company Act of 1956, as amended, we are subject to supervision, regulation and examination by the Board of Governors of the Federal Reserve System. We are also subject to the jurisdiction of the Commissioner of the Oklahoma Banking Department. As a diversified financial services provider, we pursue the objective of achieving long-term sustainable growth by balancing growth opportunities against profit, while mitigating risks inherent in the financial services industry. We conduct virtually all of our operating activities through our wholly owned subsidiary, BancFirst, a state-chartered bank headquartered in Oklahoma City, Oklahoma. BancFirst offers a full range of banking services through 86 branch offices throughout Oklahoma.

Selected Unaudited Historical and Pro Forma Financial Information. Set forth below is condensed consolidated historical financial information of the Company and its subsidiaries. The historical financial information for the year ended December 31, 2006 was derived from the audited consolidated financial

statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2006 (the “Company’s 2006 Annual Report”), and other information contained in the Company’s 2006 Annual Report, and the historical financial information as of and for the six months ended June 30, 2007 was derived from the unaudited consolidated financial statements included in the Company’s Current Report on Form 8-K dated July 25, 2007 (the “Company’s Second Quarter Earnings Report”), all of which has been incorporated by reference as described below. The selected historical financial data and the pro forma financial information should be read in conjunction with our historical financial statements included in the Company’s 2006 Annual Report and the Company’s Second Quarter Earnings Report, which have been filed with the SEC (copies of which may be obtained as set forth below under “Where You Can Find More Information”) and are incorporated by reference into this Offer to Purchase.

The unaudited pro forma balance sheet assumes the following as of June 30, 2007: (i) the purchase of 500,000 Shares in the Offer at the maximum purchase price of $45.00 per share for an aggregate purchase price of approximately $22,500,000, (ii) the reduction in outstanding Shares as a result of such purchase, and (iii) related fees and income tax liabilities.

The unaudited pro forma financial information is intended for information purposes only and does not purport to represent what our results of operations and financial condition would have been had the transactions described above actually occurred as of the dates indicated, nor does it project our results of operations for any future period or our financial condition at any future date. Such information has been prepared based upon currently available information and assumptions we believe are reasonable. Such currently available information and assumptions may prove to be inaccurate over time.

Where You Can Find More Information. We are subject to the informational filing requirements under the Exchange Act, and, accordingly, are obligated to file reports, statements and other information with the SEC relating to our business, financial condition and other matters. We also have filed a Tender Offer Statement on Schedule TO (the “Schedule TO”) with the SEC that includes additional information relating to the Offer. You may access and read our SEC filings, including the complete Schedule TO, all of the exhibits to it, and the documents incorporated therein by reference through the SEC’s Internet site at www.sec.gov. You may also read and copy any document we file at the SEC’s public reference rooms in Washington, D.C. at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the public reference rooms.

Incorporation by Reference. The rules of the SEC allow us to “incorporate by reference” information into this document, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The following documents contain important information about us and we incorporate them by reference:

Any statement contained in this Offer to Purchase or in a document incorporated herein by reference into this Offer to Purchase shall be deemed to be modified or superseded to the extent such statement is made in any subsequently filed document which is also filed as an amendment to the Schedule TO. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Offer to Purchase.

You can obtain any of the documents incorporated by reference in this document from the SEC’s website at the address described above. You may also request a copy of these documents, at no cost, by writing or telephoning the Information Agent at its address and telephone number set forth below.

11. Interests of Directors, Executive Officers and Affiliates; Recent Securities Transactions; Transactions and Arrangements Concerning the Shares.

Interests of Directors, Executive Officers and Affiliates. As of July 31, 2007, we had 15,724,536 issued and outstanding Shares and 1,253,859 Shares reserved for issuance upon exercise of all outstanding stock options and vesting of all outstanding restricted stock units. The 500,000 Shares that BancFirst Corporation is offering to purchase pursuant to the Offer represent approximately 3.2 % of the Shares outstanding on July 31, 2007.

As of July 31, 2007, our directors and executive officers as a group (35 persons) beneficially owned an aggregate of 7,420,443 shares of the Company’s Common Stock (47.19% of the total shares outstanding at that date), excluding 355,361 shares represented by options exercisable within 60 days. Our directors and executive officers have advised us that they do not intend to tender any of their Shares in the Offer, with the exception of Robert A. Gregory, a director, who has indicated his intention to tender 3,000 Shares, and Mike Rogers, Executive Vice President-Human Resources, who has indicated his intention to tender 4,000 shares. Accordingly, assuming we purchase 500,000 Shares in the Offer, the proportional holdings of our directors and executive officers will increase to approximately 48.72%. However, our directors and executive officers may, in compliance with stock ownership guidelines and applicable law, sell their Shares in open market transactions at prices that may or may not be more favorable than the Purchase Price to be paid to our shareholders in the Offer.

The following table provides information with respect to the expected beneficial ownership of our Common Stock by (i) all persons known by us to own beneficially more than 5% of our Common Stock, (ii) each of our directors, (iii) each of our executive officers and (iv) all directors and executive officers as a group. We based the share amounts on each person’s beneficial ownership of our Common Stock as of July 31, 2007. Assuming we purchase an aggregate of 500,000 Shares in the Offer, and no director or executive officer other than Messrs. Gregory and Rogers tenders any Shares in the Offer, the percentage beneficial ownership of each director and executive officer after the Offer will be approximately as set forth in the table below.

Beneficial ownership is determined in accordance with the rules of the SEC. In computing the number of Shares beneficially owned by a person and the percentage ownership of that person, Shares subject to (i) options held by that person that are currently exercisable or exercisable within 60 days of the date of this Offer to Purchase, are deemed issued and outstanding. These Shares, however, are not deemed outstanding for purposes of computing percentage ownership of each other shareholder.

Except as otherwise noted in the footnotes below, each person or entity identified below has sole voting and investment power with respect to such securities.

Our directors and executive officers are entitled to participate in the Offer on the same basis as other shareholders; however, none of our directors and executive officers intends to tender any of their Shares in the Offer, with the exception of Robert A. Gregory, a director, who has indicated his intention to tender 3,000 Shares, and Mike Rogers, Executive Vice President-Human Resources, who has indicated his intention to tender 4,000 Shares.

Recent Securities Transactions. Based on the Company’s records and information provided to the Company by its directors, executive officers, associates and subsidiaries, neither the Company, nor, to the best of the Company’s knowledge, any directors or executive officers of the Company or any associates or subsidiaries of the Company, has effected any transactions in Shares during the 60 day-period before the date hereof, except as set forth below:

Equity-Based Retirement Plans. The Company maintains a 401(k) employee savings and retirement plan, as well as an employee stock ownership plan (“ESOP”), both of which are broad-based plans covering all full-time employees, including the Company’s executive officers, who have attained the age of 21 years and who have completed six months of employment during the year. The Company’s matching contribution to the 401(k) plan equals 50% of the first 6% of pay that is contributed by a participating employee to the plan. Benefits under the ESOP are based solely on the amount contributed by the Company, which is used to purchase the Company’s common stock. A participant’s allocation is the total employer contribution multiplied by the ratio of that participant’s applicable compensation over the amount of such compensation for all participants for that year. The total amount contributed by the Company to the ESOP for 2006 was $2,202,000, and the total amount contributed by the Company to the 401(k) plan in 2006 was $1,199,000. The decision to make a contribution to the ESOP is within the sole discretion of the Board and there are no specific performance measures set forth in the ESOP.

Stock Option Plans. Executive officers receive equity compensation awards in the form of incentive stock options under the BancFirst Corporation Stock Option Plan. The stock options are designed to align the interests of the executive officers with the shareholders’ long-term interests by providing them with equity awards that are exercisable at the rate of 25% per year beginning four years from the date of grant. Typically, option grants have been made either as an employment incentive in connection with the Company’s efforts to employ an executive officer, or as a retention device. The Company’s stock option plan was adopted by the board of directors in 1986 and has been amended several times since its adoption to increase the number of shares issuable under the plan and to extend the term of the plan, which currently extends to December 31, 2011. The most recent amendment was approved by shareholders in 2006. The plan is administered by the board of directors, which has delegated to the Executive Committee the authority to designate the officers and other employees who will receive grants of stock options under the plan, and to determine the number of options to be received by any such optionee. All awards granted under the plan are ratified by our board of directors, while option grants made to executive officers are also subject to the approval of the Compensation Committee. In practice, the Executive Committee acts upon recommendations of the CEO and Mr. Brand, the president and chief executive officer of the Bank, regarding awards to the other executive officers. The Company does not have a target ownership level of equity holdings by its executives.

All stock options granted under the Company’s Stock Option Plan are made at the closing price of the Company’s common stock on the date of grant. The number of Shares authorized for grant under the Stock Option Plan is 2,500,000 Shares. As of July 31, 2007, the number of Shares available for grant under the Stock Option Plan was 100,610 Shares.

A grant of 10,000 options is made to each non-employee director at the time of his initial appointment or election to the Board under the BancFirst Corporation Non-Employee Directors’ Stock Option Plan (the “Directors’ Stock Plan”). Options granted under the Directors’ Stock Plan are exercisable at the rate of 25% per year beginning one year from the date of grant. If a director is terminated for cause, all options will be forfeited immediately. If a director ceases to be a member of the Board for any other reason, unvested options will terminate and only previously vested options may be exercised for a period of 30 days following termination (or 12 months in the case of termination on account of death).

Other Stock-Based Plans. Non-employee directors can elect to defer all or any portion of their cash compensation through the BancFirst Corporation Directors’ Deferred Stock Compensation Plan (the “Deferred Stock Compensation Plan”). Under the plan, directors of the Company and members of the community advisory boards of the Bank may defer up to 100% of their Board fees. They are credited for each deferral with a number of stock units based on the current market price of the Company’s stock, which accumulate in an account until such time as the director or community board member terminates service as a Board member. Shares of our common stock are then distributed to the terminating director or community board member based upon the number of stock units accumulated in his or her account. Because stock units are not actual shares of our common stock, they do not have any voting rights.

General. Except as otherwise described herein, neither BancFirst Corporation nor, to the best of the Company’s knowledge, any of its affiliates, directors or executive officers, is a party to any agreement, arrangement or understanding with any other person relating, directly or indirectly, to the Offer or with respect to any securities of BancFirst Corporation, including, but not limited to, any agreement, arrangement or understanding concerning the transfer or the voting of the securities of BancFirst Corporation, joint ventures, loan or option arrangements, puts or calls, guarantees of loans, guarantees against loss, or the giving or withholding of proxies, consents or authorizations.

Except as described above, we are not aware of any license or regulatory permit that appears material to our business that might be adversely affected by the acquisition of Shares as contemplated by the Offer or of any

approval or other action by any government or governmental, administrative or regulatory authority or agency, domestic, foreign or supranational, that would be required for the acquisition of Shares by us as contemplated by the Offer. Should any approval or other action be required, we presently contemplate that we will seek that approval or other action. We are unable to predict whether it will be required to delay the acceptance for payment of or payment for Shares tendered under the Offer pending the outcome of any such matter. There can be no assurance that any approval or other action, if needed, would be obtained or would be obtained without substantial cost or conditions or that the failure to obtain the approval or other action might not result in adverse consequences to our business and financial condition. Our obligation under the Offer to accept for payment and pay for Shares is subject to conditions. See Section 7.

The following describes the material United States federal income tax consequences relevant to the Offer for U.S. Holders (as defined below). This discussion is based upon the Internal Revenue Code of 1986, as amended (the “Code”), existing and proposed Treasury Regulations, administrative pronouncements and judicial decisions, changes to which could materially affect the tax consequences described herein and could be made on a retroactive basis.

This discussion deals only with Shares held as capital assets and does not deal with all tax consequences that may be relevant to all categories of holders (such as dealers in securities or commodities, traders in securities that elect to mark their holdings to market, financial institutions, regulated investment companies, real estate investment trusts, holders whose functional currency is not the United States dollar, insurance companies, tax-exempt organizations or persons who hold Shares as part of a hedging, conversion or constructive sale transaction or as a position in a straddle). In particular, different rules may apply to Shares acquired as compensation (including Shares acquired upon the exercise of options or the vesting of restricted share units). This discussion does not address the state, local or foreign tax consequences of participating in the Offer. Holders of Shares should consult their tax advisors as to the particular consequences to them of participation in the Offer.

As used herein, a “U.S. Holder” means a beneficial holder of Shares that is for United States federal income tax purposes: (a) an individual citizen or resident of the United States, (b) a corporation or a partnership created or organized in or under the laws of the United States, any state thereof or the District of Columbia, or (c) an estate or trust the income of which is subject to United States federal income taxation regardless of its source.

Holders of Shares who are not U.S. Holders (“foreign shareholders”) should consult their tax advisors regarding the United States federal income tax consequences and any applicable foreign tax consequences of the Offer and also should see Section 3 for a discussion of the applicable United States withholding tax rules and the potential for obtaining a refund of all or a portion of any tax withheld.

If a partnership holds Shares, the tax treatment of a partner will generally depend upon the status of the partner and the activities of the partnership. Holders that are partners of a partnership holding Shares should consult their own tax advisors.

Non-Participation in the Tender Offer. U.S. Holders who do not participate in the Offer will not incur any tax liability as a result of the consummation of the Offer.

Exchange of Shares Pursuant to the Offer. An exchange of Shares for cash pursuant to the Offer will be a taxable transaction for United States federal income tax purposes. A U.S. Holder who participates in the Offer will be treated, depending on such U.S. Holder’s particular circumstances, either as recognizing gain or loss from the disposition of the Shares or as receiving a dividend distribution from us.

Under Section 302 of the Code, a U.S. Holder will recognize gain or loss on an exchange of Shares for cash if the exchange (a) results in a “complete termination” of all such U.S. Holder’s equity interest in us, (b) results in a “substantially disproportionate” redemption with respect to such U.S. Holder, or (c) is “not essentially

equivalent to a dividend” with respect to the U.S. Holder. In applying the Section 302 tests, a U.S. Holder must take account of stock that such U.S. Holder constructively owns under attribution rules, pursuant to which the U.S. Holder will be treated as owning our Shares owned by certain family members (except that in the case of a “complete termination” a U.S. Holder may waive, under certain circumstances, attribution from family members) and related entities and our stock that the U.S. Holder has the right to acquire by exercise of an option. An exchange of Shares for cash will be a substantially disproportionate redemption with respect to a U.S. Holder if (i) the percentage of the then outstanding Shares owned by such U.S. Holder in us immediately after the exchange is less than 80% of the percentage of the Shares owned by such U.S. Holder in us immediately before the exchange, and (ii) the percentage of the then outstanding voting stock owned by such U.S. Holder in us immediately after the exchange is less than 80% of the percentage of the voting stock owned by such U.S. Holder in us immediately before the exchange. If an exchange of Shares for cash fails to satisfy the “substantially disproportionate” test, the U.S. Holder nonetheless may satisfy the “not essentially equivalent to a dividend” test. An exchange of Shares for cash will satisfy the “not essentially equivalent to a dividend” test if it results in a “meaningful reduction” of the U.S. Holder’s equity interest in us. An exchange of Shares for cash that results in a reduction of the proportionate equity interest in us of a U.S. Holder whose relative equity interest in us is minimal (an interest of less than one percent should satisfy this requirement) and who does not exercise any control over or participate in the management of our corporate affairs should be treated as “not essentially equivalent to a dividend.” U.S. Holders should consult their tax advisors regarding the application of the rules of Section 302 in their particular circumstances.

If a U.S. Holder is treated as recognizing gain or loss from the disposition of the Shares for cash, such gain or loss will be equal to the difference between the amount of cash received and such U.S. Holder’s tax basis in the Shares exchanged therefor. Any such gain or loss will be capital gain or loss and will be long-term capital gain or loss if the holding period of the Shares exceeds one year as of the date of the exchange.

If a U.S. Holder is not treated under the Section 302 tests as recognizing gain or loss on an exchange of Shares for cash, the entire amount of cash received by such U.S. Holder pursuant to the exchange will be treated as a dividend to the extent of the portion of our current and accumulated earnings and profits allocable to such Shares. Provided certain holding period requirements are satisfied, non-corporate holders generally will be subject to United States federal income tax at a maximum rate of 15% on amounts treated as dividends, i.e., the entire amount of cash received without reduction for the tax basis of the Shares exchanged. To the extent that cash received in exchange for Shares is treated as a dividend to a corporate U.S. Holder, (a) it will be eligible for a dividends-received deduction (subject to applicable limitations) and (b) it will be subject to the “extraordinary dividend” provisions of the Code. U.S. Holders should consult their tax advisors concerning the rules discussed in this paragraph in light of their particular circumstances.

To the extent that amounts received pursuant to the Offer exceed a U.S. Holder’s allocable share of our current and accumulated earnings and profits, the distribution will first be treated as a non-taxable return of capital, causing a reduction in the adjusted basis of such U.S. Holder’s Shares, and any amounts in excess of the U.S. Holder’s adjusted basis will constitute capital gain. Any remaining adjusted basis in the Shares tendered will be transferred to any remaining Shares held by such U.S. Holder.

We cannot predict whether or the extent to which the Offer will be oversubscribed. If the Offer is oversubscribed, proration of tenders pursuant to the Offer will cause us to accept fewer Shares than are tendered. Therefore, a U.S. Holder can be given no assurance that a sufficient number of such U.S. Holder’s Shares will be purchased pursuant to the Offer to ensure that such purchase will be treated as a sale or exchange, rather than as a dividend, for United States federal income tax purposes pursuant to the rules discussed above.

Tax Considerations for Participants in our Retirement Plans. Special tax rules will apply with respect to Shares tendered through our retirement plans. Please refer to the “Letter to Participants in The BancFirst Corporation Employee Stock Ownership Plan” and/or “Letter to Participants in The BancFirst Corporation Thrift Plan” for a discussion of the tax rules applicable to shares allocated pursuant to our retirement plans.

Tax Considerations for Holders of Vested Stock Options. Holders of vested stock options should consult their own tax advisors as to the special tax rules that may be applicable upon the exercise of any such options and the tender of any Shares acquired through such option exercise pursuant to the Offer.

See Section 3 with respect to the application of United States federal income tax withholding and backup withholding.

14. Effects of the Offer on the Market for Shares; Registration under the Exchange Act.

The purchase by BancFirst Corporation of Shares under the Offer will reduce our “public float” (the number of Shares owned by non-affiliate shareholders and available for trading in the securities markets). This reduction in our public float may result in lower stock prices and/or reduced liquidity in the trading market for the Shares following completion of the Offer.

We anticipate that there will be a sufficient number of Shares outstanding and publicly traded following completion of the Offer to ensure a continued trading market for such Shares. However, we may amend or terminate the Offer, and will not be required to accept for purchase any Shares tendered if, in our good faith reasonable judgment, any purchase of Shares under the Offer could result in the Offer being considered a “going private transaction” under Rule 13e-3 under the Exchange Act, that is:

Based upon published guidelines of the Nasdaq, we do not believe that our purchase of Shares under the Offer will cause the remaining outstanding Shares to be delisted from the Nasdaq or to be held of record by fewer than 300 persons and thus eligible for deregistration under the Exchange Act. The Shares are registered under the Exchange Act, which requires, among other things, that we furnish certain information to our shareholders and the SEC and comply with the SEC’s proxy rules in connection with meetings of our shareholders. We believe that our purchase of Shares under the Offer will not result in the Shares becoming eligible for deregistration under the Exchange Act.

This Offer is not intended to be the first stage in a series of transactions that is reasonably likely to produce a going-private effect within the meaning of Rule 13e-3 under the Exchange Act.

The Shares are “margin securities” under the rules of the Board of Governors of the Federal Reserve System. This classification has the effect, among other things, of allowing brokers to extend credit to their customers using the Shares as collateral. BancFirst Corporation believes that, following the purchase of Shares under the Offer, the Shares remaining outstanding will continue to be margin securities for purposes of the Federal Reserve Board’s margin rules and regulations.

We expressly reserve the right, in our sole discretion, at any time and from time to time, and regardless of whether or not any of the events set forth in Section 7 shall have occurred or shall be deemed by us to have occurred, to extend the period of time during which the Offer is open and thereby delay acceptance for payment of, and payment for, any Shares by giving oral or written notice of such extension to the Depositary and making a public announcement of such extension.

We also expressly reserve the right, in our sole discretion, to terminate the Offer and reject for payment and not pay for any Shares not theretofore accepted for payment or paid for, or, subject to applicable law, to postpone payment for Shares upon the occurrence of any of the conditions specified in Section 7 by giving oral or written notice of the termination or postponement to the Depositary and making a public announcement of the termination or postponement. Our reservation of the right to delay payment for Shares which we have accepted for payment is limited by Rule 13e-4(f)(5) under the Exchange Act, which requires that we must pay the consideration offered or return the Shares tendered promptly after termination or withdrawal of an Offer. Subject to compliance with applicable law, we further reserve the right, in our sole discretion, and regardless of whether any of the events set forth in Section 7 have occurred or are deemed by us to have occurred, to amend the Offer in any respect (including, without limitation, by decreasing or increasing the consideration offered in the Offer to holders of Shares or by decreasing or increasing the number of Shares being sought in the Offer). Amendments to the Offer may be made at any time and from time to time by public announcement of the amendment. In the case of an extension, the notice of the amendment must be issued no later than 9:00 a.m., New York City time, on the next business day after the last previously scheduled or announced Expiration Date. Any public announcement made pursuant to the Offer will be disseminated promptly to shareholders in a manner reasonably designed to inform shareholders of the change. In addition, we would file such press release as an exhibit to the Schedule TO.

If we materially change the terms of the Offer or the information concerning the Offer, or if we waive a material condition of the Offer, we will extend the Offer to the extent required by Rules 13e-4(d)(2) and 13e-4(e)(3) under the Exchange Act. These rules provide that the minimum period during which an offer must remain open following material changes in the terms of the offer or information concerning the offer (other than a change in price or a change in percentage of securities sought) will depend on the facts and circumstances, including the relative materiality of the terms or information. If:

(1) we increase or decrease the price to be paid for Shares, materially increase the Dealer Manager’s fee or increase or decrease the number of Shares being sought in the Offer and, in the event of an increase in the number of Shares being sought, the increase exceeds 2% of the Shares outstanding, and

(2) the Offer is scheduled to expire at any time earlier than the expiration of a period ending on the tenth business day from, and including, the date that notice of an increase or decrease is first published, sent or given in the manner specified in this Section 15,

then in each case the Offer will be extended until the expiration of the period of ten business days. For purposes of the Offer, a “business day” means any day other than a Saturday, Sunday or Federal holiday and consists of the time period from 12:01 a.m. through 5:00 p.m., New York City time.

Friedman, Billings, Ramsey & Co., Inc. (“Friedman, Billings, Ramsey”) will act as the Dealer Manager and MacKenzie Partners, Inc. will act as the Information Agent for us in connection with the Offer. The Dealer Manager and Information Agent may contact stockholders by mail, telephone, facsimile, telex, telegraph, other electronic means and personal interviews, and may request brokers, dealers and other nominee stockholders to forward materials relating to the offer to beneficial owners. We agreed to pay Friedman, Billings, Ramsey upon acceptance for and payment of Shares pursuant to the Offer, a total of 0.75% of the total dollar amount of the Shares acquired by the Company pursuant to the Offer. In the event that the consummation of the Tender would result in a Rule 13e-3 transaction (as such term is defined in Rule 13e-3(a)(3) under the Exchange Act), and we determine to terminate the Offer, we have agreed to pay Friedman, Billings Ramsey a fee of $50,000.

We agreed to pay MacKenzie Partners, Inc. a retainer of $10,000 plus reasonable fees and expenses. Friedman, Billings, Ramsey and MacKenzie Partners, Inc. will also be reimbursed for certain out-of-pocket expenses. Friedman, Billings, Ramsey and MacKenzie Partners, Inc. will also be indemnified against certain liabilities, including liabilities under the federal securities laws, in connection with the offer.

During the past two years, Friedman, Billings, Ramsey has not received any compensation from us for any investment banking or other financial advisory services. Friedman, Billings, Ramsey may provide such services to us in the future and may receive compensation for such services. In addition, in the ordinary course of its business as a broker-dealer, Friedman, Billings, Ramsey may also purchase securities from and sell securities to us. Friedman, Billings, Ramsey may also actively trade the equity securities of BancFirst Corporation for its own account and for the accounts of its customers and, accordingly, may at any time hold a long or short position in such securities.

We have retained American Stock Transfer & Trust Company to act as Depositary in connection with the Offer. American Stock Transfer & Trust Company will receive base compensation of $20,000 for its services and will also be reimbursed for reasonable out-of-pocket expenses. We agreed to indemnify American Stock Transfer & Trust Company against certain liabilities, including certain liabilities under the federal securities laws, in connection with the offer. American Stock Transfer & Trust Company has not been retained to make solicitations or recommendations in connection with this Offer.

Certain officers and employees of the Company may render services in connection with the Offer but they will not receive any additional compensation for such services.

We will not pay any fees or commissions to brokers, dealers, commercial banks, trust companies or other nominees (other than fees to the Information Agent and the Dealer Manager) for soliciting tenders of Shares pursuant to the Offer. Shareholders holding Shares through brokers, dealers, commercial banks, trust companies or other nominee shareholders are urged to consult the brokers, banks and other nominee shareholders to determine whether transaction costs may apply if shareholders tender Shares through the brokers, dealers, commercial banks, trust companies or other nominee shareholders and not directly to the Depositary. We will, however, upon request, reimburse brokers, dealers and commercial banks for customary mailing and handling expenses incurred by them in forwarding the Offer and related materials to the beneficial owners of Shares held by them as a nominee or in a fiduciary capacity. No broker, dealer, commercial bank, trust company or other nominee has been authorized to act as the agent of BancFirst Corporation, the Information Agent or the Depositary for purposes of the Offer. We will pay or cause to be paid all stock transfer taxes, if any, on the purchase of Shares in the Offer, except as otherwise described in Section 5.

We are not aware of any jurisdiction where the making of the Offer is not in compliance with applicable law. If we become aware of any jurisdiction where the making of the Offer or the acceptance of Shares pursuant to the Offer is not in compliance with any valid applicable law, we will make a good faith effort to comply with the applicable law. If, after a good faith effort, we cannot comply with the applicable law, the Offer will not be made to, nor will tenders be accepted from or on behalf of, the holders of Shares residing in that jurisdiction. In any jurisdiction where the securities, blue sky or other laws require the Offer to be made by a licensed broker or dealer, the Offer will be deemed to be made on our behalf by one or more registered brokers or dealers licensed under the laws of the jurisdiction.

Pursuant to Rule 13e-4 under the Exchange Act, we have filed with the SEC a Tender Offer Statement on Schedule TO, which contains additional information relating to the Offer. The Schedule TO, including the exhibits and any amendments thereto, may be examined, and copies may be obtained, at the same places and in the same manner set forth in Section 10 with respect to information concerning BancFirst Corporation. Our Board of Directors has authorized the purchase of up to 1,520,362 Shares of the Company’s outstanding Common Stock under an open-market stock repurchase program adopted in November 1999, under which 233,052 Shares may yet be purchased as of July 31, 2007. However, Rule 13e-4(f) under the Exchange Act prohibits us from purchasing any Shares, other than in the Offer, until at least ten business days have elapsed after the Expiration Date. Accordingly, any additional purchases outside the Offer may not be consummated until at least ten business days have elapsed after the Expiration Date. See Section 2.

Tendering shareholders should rely only on the information contained in this document or to which we have referred you. We have not authorized anyone to provide you with information or make any representation on behalf of us or in connection with the Offer other than those contained in this Offer to Purchase, the related Letter of Transmittal or in the other documents that constitute a part of the Offer. If any such representation is given or made, you should not rely on that information or representation as having been authorized by us or the Dealer Manager.

Facsimile copies of the Letter of Transmittal, properly completed and duly signed, will be accepted. The Letter of Transmittal, book-entry confirmation of Shares and any other required documents should be sent or delivered by each shareholder of BancFirst Corporation or his/her broker, dealer, commercial bank, trust company or other nominee to the Depositary, at one of the addresses set forth below:

Questions or requests for assistance may be directed to the Information Agent or the Dealer Manager at their respective telephone numbers and addresses set forth below. Questions or requests for assistance or additional copies of the Offer to Purchase and the Letter of Transmittal or the Notice of Guaranteed Delivery may be directed to the Information Agent at the address and telephone number set forth below. Shareholders may also contact their broker, dealer, commercial bank or trust company for assistance concerning the Offer.


	Price Range
	High		Low		Cash Dividends Declared
Year Ended December 31,
2007
First Quarter	$	55.210	$	44.160	$	0.18
Second Quarter	$	48.200	$	41.940	$	0.18

2006
First Quarter	$	44.000	$	39.755	$	0.16
Second Quarter	$	46.420	$	42.080	$	0.16
Third Quarter	$	48.450	$	41.890	$	0.18
Fourth Quarter	$	55.180	$	46.100	$	0.18

2005
First Quarter	$	40.125	$	33.210	$	0.14
Second Quarter	$	43.915	$	31.455	$	0.14
Third Quarter	$	45.350	$	40.980	$	0.16
Fourth Quarter	$	42.830	$	39.170	$	0.16


	Six Months Ended June 30,						Year Ended December 31,
	2007			2006			2006			2005
Income Statement Data
Net interest income	$	73,811		$	70,354		$	143,688		$	131,451
Provision for loan losses		101			1,598			1,790			4,607
Noninterest income		29,117			28,141			58,424			54,284
Noninterest expense		65,039			61,118			124,557			117,164
Net income		24,525			23,090			49,352			42,836
Balance Sheet Data
Total assets	$	3,601,866		$	3,389,689		$	3,418,574		$	3,223,030
Securities		459,271			434,696			432,910			456,222
Total loans (net of unearned interest)		2,345,838			2,339,959			2,325,548			2,317,426
Allowance for loan losses		27,568			28,227			27,700			27,517
Deposits		3,151,553			2,954,960			2,974,305			2,804,519
Stockholders’ equity		364,547			320,430			348,355			302,349
Per Common Share Data
Net income—basic	$	1.56		$	1.47		$	3.14		$	2.74
Net income—diluted		1.52			1.44			3.07			2.68
Cash dividends		0.36			0.32			0.68			0.60
Book value		23.18			20.39			22.10			19.34
Tangible book value		20.46			17.95			19.57			16.87
Selected Financial Ratios
Performance ratios:
Return on average assets		1.41	%		1.40	%		1.46	%		1.39	%
Return on average stockholders’ equity		13.90			14.76			15.10			14.80
Cash dividend payout ratio		23.08			21.77			21.73			21.90
Net interest spread		3.67			3.91			3.80			4.13
Net interest margin		4.72			4.75			4.75			4.76
Efficiency ratio		63.19			61.63			61.63			63.08
Balance Sheet Ratios:
Average loans to deposits		75.02	%		79.13	%		79.19	%		82.43	%
Average earning assets to total assets		90.74			90.16			90.20			90.19
Average stockholders’ equity to average assets		10.11			9.46			9.68			9.37
Asset Quality Ratios:
Nonperforming and restructured loans to total loans		0.66	%		0.37	%		0.51	%		0.40	%
Nonperforming and restructured assets to total assets		0.46			0.33			0.40			0.36
Allowance for loan losses to total loans		1.18			1.21			1.19			1.19
Allowance for loan losses to nonperforming and restructured loans		177.18			328.88			231.41			293.36
Net chargeoffs to average loans		0.01			0.08			0.09			0.14


	Shares Purchased At
	$39.50 per share			$45.00 per share
Income Statement Data
Net interest income	$	73,293		$	73,220
Noninterest expense		29,117			29,117
Net income		24,188			24,141
Balance Sheet Data
Total assets	$	3,581,466		$	3,578,716
Stockholders’ equity		343,810			341,013
Per Common Share Data
Net income—basic	$	1.59		$	1.58
Net income—diluted		1.55			1.55
Book value		21.86			21.69
Capital Ratios
Leverage Ratio		9.27	%		9.20	%
Total Capital Ratio		13.28	%		13.18	%


	Amount of Beneficial Ownership		Percent of Class		Percentage to be Owned after Offer
David E. Rainbolt P.O. Box 26788 Oklahoma City, OK 73126	6,124,462	⁽¹⁾	38.95	%	40.23	%

Investors Trust Company P. O. Box 400 Duncan, OK 73534	1,056,770	⁽²⁾	6.72	%	6.94	%

BancFirst Corporation Employee Stock Ownership Plan (the “ESOP”) and BancFirst Corporation Thrift Plan (the “Thrift Plan” and, together with the ESOP, the “Retirement Plans”) P.O. Box 26788 Oklahoma City, OK 73126	999,115	⁽³⁾	6.35	%	6.56	%

Dennis L. Brand	38,338	⁽⁴⁾	0.24	%	0.25	%
E. Wayne Cardwell	22,082	⁽⁵⁾	0.14	%	0.15	%
Scott Copeland	10,243	⁽⁶⁾	0.07	%	0.07	%
C. L. Craig, Jr.	34,934	⁽⁷⁾	0.22	%	0.23	%
William H. Crawford	345,688	⁽⁸⁾	2.20	%	2.27	%
James R. Daniel	28,182	⁽⁹⁾	0.18	%	0.18	%
Roy C. Ferguson	31,503	⁽¹⁰⁾	0.20	%	0.21	%
Randy Foraker	10,854	⁽¹¹⁾	0.07	%	0.07	%
K. Gordon Greer	27,681	⁽¹²⁾	0.18	%	0.18	%
Robert A. Gregory	5,496	⁽¹³⁾	0.03	%	0.02	%
Dr. Donald B. Halverstadt	7,500	⁽¹⁴⁾	0.05	%	0.05	%
D. Jay Hannah	28,208	⁽¹⁵⁾	0.18	%	0.19	%
David R. Harlow	11,695	⁽¹⁶⁾	0.07	%	0.08	%
John C. Hugon	100,484	⁽¹⁷⁾	0.64	%	0.66	%
Karen James	57,871	⁽¹⁸⁾	0.37	%	0.38	%
William O. Johnstone	15,455	⁽¹⁹⁾	0.10	%	0.10	%
Dave R. Lopez	5,870	⁽²⁰⁾	0.04	%	0.04	%
J. Ralph McCalmont	195,000	⁽²¹⁾	1.24	%	1.28	%
Tom H. McCasland, III	152,790	⁽²²⁾	0.97	%	1.00	%
Marion McMillan	37,099	⁽²³⁾	0.24	%	0.24	%
Melvin Moran	135,858	⁽²⁴⁾	0.86	%	0.89	%


	Amount of Beneficial Ownership		Percent of Class		Percentage to be Owned after Offer
Robert M. Neville	39,851	⁽²⁵⁾	0.25	%	0.26	%
Ronald J. Norick	13,000	⁽²⁶⁾	0.08	%	0.09	%
Paul B. Odom, Jr.	36,000	⁽²⁷⁾	0.23	%	0.24	%
Dale E. Petersen	17,321	⁽²⁸⁾	0.11	%	0.11	%
David E. Ragland	16,016	⁽²⁹⁾	0.10	%	0.11	%
H. E. Rainbolt	63,207	⁽³⁰⁾	0.40	%	0.42	%
J. Michael Rogers	10,863	⁽³¹⁾	0.07	%	0.07	%
Darryl Schmidt	25,449	⁽³²⁾	0.16	%	0.17	%
David M. Seat	25,432	⁽³³⁾	0.16	%	0.17	%
Joe T. Shockley, Jr.	40,743	⁽³⁴⁾	0.26	%	0.27	%
Kendal W. Starks	25,629	⁽³⁵⁾	0.16	%	0.17	%
David Westman	200		0.00	%	0.00	%
G. Rainey Williams, Jr.	34,800	⁽³⁶⁾	0.22	%	0.23	%
All directors and executive officers as a group (35 persons)	7,775,804		48.36	%	49.89	%


		Page
SECTION

SUMMARY TERM SHEET		i
CAUTIONARY NOTICE REGARDING FORWARD-LOOKING STATEMENTS		ix
INTRODUCTION		1
THE OFFER		4
1.	Number of Shares; Purchase Price Proration	4
2.	Purpose of the Offer; Certain Effects of the Offer	6
3.	Procedures for Tendering Shares	9
4.	Withdrawal Rights	15
5.	Purchase of Shares and Payment of Purchase Price	16
6.	Conditional Tender of Shares	17
7.	Conditions of the Offer	17
8.	Price Range of Shares; Dividends; Rights Agreement	20
9.	Source and Amount of Funds	23
10.	Certain Information Concerning the Company	23
11.	Interests of Directors, Executive Officers and Affiliates; Recent Securities Transactions; Transactions and Arrangements Concerning the Shares	27
12.	Certain Legal Matters; Regulatory Approvals	32
13.	United States Federal Income Tax Consequences	33
14.	Effects of the Offer on the Market for Shares; Registration under the Exchange Act	35
15.	Extension of the Offer; Termination; Amendment	35
16.	Fees and Expenses	36
17.	Miscellaneous	37


Name	Date of Transaction	Nature of Transaction	Amount	Price
Employee Stock Ownership Plan	June 4, 2007	Market Purchase	7,000	$	43.80
	June 5, 2007	Market Purchase	1,001	$	43.33


By Mail or Overnight Courier:		By Hand:

American Stock Transfer & Trust Company Operations Center Attn: Reorganization Department 6201 15th Avenue Brooklyn, New York 11219		American Stock Transfer & Trust Company Attn: Reorganization Department 59 Maiden Lane New York, New York 10038