S-3ASR

As filed with the Securities and Exchange Commission on March 28, 2013

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ATMOS ENERGY CORPORATION

(Exact name of registrant as specified in its charter)

Texas and Virginia	75-1743247
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
1800 Three Lincoln Centre 5430 LBJ Freeway Dallas, Texas 75240 (972) 934-9227	Louis P. Gregory 1800 Three Lincoln Centre 5430 LBJ Freeway Dallas, Texas 75240 (972) 934-9227
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)	(Name, address, including zip code, and telephone number, including area code, of agent for service)

The Commission is requested to mail copies of all orders, notices and communications to:

Robyn Zolman

Gibson, Dunn & Crutcher LLP

1801 California Street, Suite 4200

Denver, Colorado 80202

(303) 298-5700

Approximate date of commencement of proposed sale to public: From time to time after this registration statement becomes effective.

If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ¨

If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  x

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  x

If this form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer	x	Accelerated filer	¨
Non-accelerated filer	¨  (Do not check if a smaller reporting company)	Smaller reporting company	¨

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities to be Registered	Proposed Maximum Aggregate Offering Price	Amount of Registration Fee
Debt securities and common stock (no par value per share)	$1,750,000,000(1)	(2)

(1) An indeterminate number of securities is being registered as may from time to time be sold at indeterminate prices, up to a maximum aggregate offering price of $1,750,000,000. The total amount of $1,750,000,000 of securities being registered represents the offering price of any common stock, the principal amount of any debt securities issued at their stated principal amount and the offering price of any debt securities issued at an original discount. The securities being registered also include an indeterminate number of shares of common stock that may be issued upon conversion of debt securities that are being registered. Separate consideration may or may not be received for shares of common stock that are issuable upon conversion of debt securities.

(2) In accordance with Rules 456(b) and 457(r), the registrant is deferring payment of all of the registration fee.

PROSPECTUS

Atmos Energy Corporation

By this prospectus, we offer up to

$1,750,000,000

of debt securities and common stock.

We will provide specific terms of these securities in supplements to this prospectus. This prospectus may not be used to sell securities unless accompanied by a prospectus supplement. You should read this prospectus and the applicable prospectus supplement carefully before you invest.

Investing in these securities involves risks. See “Risk Factors” on page 1 of this prospectus, in the applicable prospectus supplement and in the documents incorporated by reference.

Our common stock is listed on the New York Stock Exchange under the symbol “ATO.”

Our address is 1800 Three Lincoln Centre, 5430 LBJ Freeway, Dallas, Texas 75240, and our telephone number is (972) 934-9227.

The Securities and Exchange Commission and state securities regulators have not approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus is dated March 28, 2013.

We have not authorized any other person to provide you with any information or to make any representation that is different from, or in addition to, the information and representations contained in this prospectus or in any of the documents that are incorporated by reference in this prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information appearing in this prospectus, as well as the information contained in any document incorporated by reference, is accurate as of the date of each such document only, unless the information specifically indicates that another date applies.

TABLE OF CONTENTS

	Page
Cautionary Statement Regarding Forward-Looking Statements		ii
Risk Factors		1
Atmos Energy Corporation		1
Securities We May Offer		1
Use of Proceeds		2
Retroactive Presentation for Change in Accounting Principle		3
Ratio of Earnings to Fixed Charges		3
Description of Debt Securities		4
Description of Common Stock		18
Plan of Distribution		20
Legal Matters		21
Experts		21
Where You Can Find More Information		22
Incorporation of Certain Documents by Reference		22

The distribution of this prospectus may be restricted by law in certain jurisdictions. You should inform yourself about and observe any of these restrictions. This prospectus does not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which the offer or solicitation is not authorized, or in which the person making the offer or solicitation is not qualified to do so, or to any person to whom it is unlawful to make the offer or solicitation.

The terms “we,” “our,” “us,” and “Atmos Energy” refer to Atmos Energy Corporation and its subsidiaries unless the context suggests otherwise. The term “you” refers to a prospective investor.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Statements contained or incorporated by reference in this prospectus that are not statements of historical fact are “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”). Forward-looking statements are based on management’s beliefs as well as assumptions made by, and information currently available to, management. Because such statements are based on expectations as to future results and are not statements of fact, actual results may differ materially from those stated. Important factors that could cause future results to differ include, but are not limited to:

• our ability to continue to access the credit markets to satisfy our liquidity requirements;

• the impact of adverse economic conditions on our customers;

• increased costs of providing pension and postretirement health care benefits and increased funding requirements, along with increased costs of health care benefits;

• market risks beyond our control affecting our risk management activities, including market liquidity, commodity price volatility, increasing interest rates and counterparty creditworthiness;

• regulatory trends and decisions, including the impact of rate proceedings before various state regulatory commissions;

• possible increased federal, state and local regulation of the safety of our operations;

• possible increased federal regulatory oversight and potential penalties;

• the impact of environmental regulations on our business;

• the impact of possible future additional regulatory and financial risks associated with global warming and climate change on our business;

• the concentration of our distribution, pipeline and storage operations in Texas;

• adverse weather conditions;

• the effects of inflation and changes in the availability and prices of natural gas;

• the capital-intensive nature of our natural gas distribution business;

• increased competition from energy suppliers and alternative forms of energy;

• the threat of cyber-attacks or acts of cyber-terrorism that could disrupt our business operations and information technology systems;

• the inherent hazards and risks involved in operating our natural gas distribution business or with natural disasters, terrorist activities or other events; and

• other risks and uncertainties discussed in this prospectus, any accompanying prospectus supplement and our other filings with the Securities and Exchange Commission (the “SEC”).

All of these factors are difficult to predict and many are beyond our control. Accordingly, while we believe our forward-looking statements to be reasonable, there can be no assurance that they will approximate actual experience or that the expectations derived from them will be realized. When used in our documents or oral presentations, the words “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “goal,” “intend,” “objective,” “plan,” “projection,” “seek,” “strategy” or similar words are intended to identify forward-looking statements. We undertake no obligation to update or revise our forward-looking statements, whether as a result of new information, future events or otherwise.

For additional factors you should consider generally and when evaluating these forward-looking statements, please see “Risk Factors” on page 1 of this prospectus and “Item 1A. Risk Factors” and “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the fiscal year ended September 30, 2012 and “Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our quarterly report on Form 10-Q for the three-month period ended December 31, 2012. See “Incorporation of Certain Documents by Reference,” as well as the applicable prospectus supplement.

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RISK FACTORS

Investing in our debt securities or our common stock involves risks. Our business is influenced by many factors that are difficult to predict and beyond our control and that involve uncertainties that may materially affect our results of operations, financial condition or cash flows, or the value of these securities. These risks and uncertainties include those described in the risk factors and other sections of the documents that are incorporated by reference in this prospectus. Subsequent prospectus supplements may contain a discussion of additional risks applicable to an investment in us and the particular type of securities we are offering under the prospectus supplements. You should carefully consider all of the information contained in or incorporated by reference in this prospectus or in the applicable prospectus supplement before you invest in our debt securities or common stock.

ATMOS ENERGY CORPORATION

We are engaged primarily in the regulated natural gas distribution and transmission and storage businesses, as well as other nonregulated natural gas businesses. We are one of the country’s largest natural gas-only distributors based on number of customers. We currently distribute natural gas through sales and transportation arrangements to over three million residential, commercial, public authority and industrial customers in nine states. We also operate one of the largest intrastate pipelines in Texas based upon miles of pipe.

Through our regulated transmission and storage business, we provide natural gas transportation and storage services to our Mid-Tex Division, our largest natural gas distribution division located in Texas, and to third parties. Additionally, we provide ancillary services customary to the pipeline industry, including parking arrangements, lending and sales of inventory on hand.

Through our nonregulated businesses, we primarily provide natural gas management and marketing services to municipalities, other local gas distribution companies and industrial customers primarily in the Midwest and Southeast. We also provide storage services to some of our natural gas distribution divisions and to third parties.

We operate through the following three segments:

• the natural gas distribution segment, which includes our regulated natural gas distribution and related sales operations;

• the regulated transmission and storage segment, which includes the regulated pipeline and storage operations of our Atmos Pipeline — Texas Division; and

• the nonregulated segment, which includes our nonregulated natural gas management, nonregulated natural gas transmission, storage and other services.

SECURITIES WE MAY OFFER

Types of Securities

The types of securities that we may offer and sell from time to time by this prospectus are:

• debt securities, which we may issue in one or more series and which may include provisions regarding conversion of the debt securities into our common stock; and

• common stock.

The aggregate initial offering price of all securities sold will not exceed $1,750,000,000. We will determine when we sell securities, the amounts of securities we will sell and the prices and other terms on which we will sell them. We may sell securities to or through underwriters, through agents or dealers or directly to purchasers. The offer and sale of securities by this prospectus is subject to receipt of satisfactory regulatory approvals in four states, all of which have been received and are currently in effect.

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Prospectus Supplements

This prospectus provides you with a general description of the debt securities and common stock we may offer. Each time we offer securities, we will provide a prospectus supplement that will contain specific information about the terms of the offering. The prospectus supplement may also add to or change information contained in this prospectus. In that case, the prospectus supplement should be read as superseding this prospectus.

In each prospectus supplement, which will be attached to the front of this prospectus, we will include, among other things, the following information:

• the type and amount of securities which we propose to sell;

• the initial public offering price of the securities;

• the names of the underwriters, agents or dealers, if any, through or to which we will sell the securities;

• the compensation, if any, of those underwriters, agents or dealers;

• if applicable, information about the securities exchanges or automated quotation systems on which the securities will be listed or traded;

• material United States federal income tax considerations applicable to the securities, where necessary; and

• any other material information about the offering and sale of the securities.

For more details on the terms of the securities, you should read the exhibits filed with our registration statement, of which this prospectus is a part. You should also read both this prospectus and the applicable prospectus supplement, together with additional information described under the heading “Where You Can Find More Information.”

USE OF PROCEEDS

Except as may otherwise be stated in the applicable prospectus supplement, we intend to use the net proceeds from the sale of the securities that we may offer and sell from time to time by this prospectus for general corporate purposes, including for working capital, repaying indebtedness and funding capital projects and other growth.

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RETROACTIVE PRESENTATION FOR CHANGE IN ACCOUNTING PRINCIPLE

The following is presented to reflect the retrospective application of a new accounting pronouncement with respect to the financial information contained in our Annual Report on Form 10-K for the year ended September 30, 2012. Effective October 1, 2012, we adopted Accounting Standards Update No. 2011-05, “Presentation of Comprehensive Income,” as amended by Accounting Standards Update No. 2011-12, “Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income.” These updates require that all nonowner changes in shareholders’ equity be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements and eliminate the option to present components of other comprehensive income as part of the statement of shareholders’ equity. These updates do not, however, change the items that must be reported in other comprehensive income or the determination of net income. The new guidance is to be applied retrospectively. The adoption only impacted the presentation of our consolidated financial statements.

The following selected financial information revises historical information to illustrate the new presentation required by this pronouncement for the periods presented. This data should be read in conjunction with our audited consolidated financial statements and the accompanying notes for the year ended September 30, 2012 as included in our Annual Report on Form 10-K, which is incorporated by reference in the prospectus.

Consolidated Statements of Comprehensive Income

	Year ended September 30,
	2012			2011			2010
	(In thousands)
Net income	$	216,717		$	207,601		$	205,839
Other comprehensive income (loss), net of tax:
Unrealized holding gains (losses) on available-for-sale securities, net of tax of $1,881, $(953) and $1,025		3,103			(1,647	)		1,745
Amortization and unrealized gain (loss) on interest rate agreements, net of tax of $(5,388), $(16,850) and $1,193		(10,116	)		(28,689	)		2,030
Net unrealized gains (losses) on commodity cash flow hedges, net of tax of $5,029, $3,355 and $(4,452)		7,866			5,248			(6,963	)
Total other comprehensive income (loss)		853			(25,088	)		(3,188	)
Total comprehensive income	$	217,570		$	182,513		$	202,651

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for the periods indicated:

	Three Months Ended December  31,				Year Ended September 30,
	2012		2011		2012		2011		2010		2009		2008
Ratio of earnings to fixed charges		4.65		3.54		2.84		2.78		2.78		2.55		2.76

For purposes of computing the ratio of earnings to fixed charges, earnings consists of the sum of our pretax income from continuing operations and fixed charges. Fixed charges consist of interest expense, amortization of debt discount, premium and expense, capitalized interest and a portion of lease payments considered to represent an interest factor.

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DESCRIPTION OF DEBT SECURITIES

We may issue debt securities from time to time in one or more distinct series. This section summarizes the material terms that we anticipate will be common to all series of debt securities. Please note that the terms of any series of debt securities that we may offer may differ significantly from the common terms described in this prospectus. Many of the other terms of any series of debt securities that we offer, and any differences from the common terms described in this prospectus, will be described in the prospectus supplement for such securities to be attached to the front of this prospectus.

As required by U.S. federal law for all bonds and notes of companies that are publicly offered, a document called an indenture will govern any debt securities that we issue. An indenture is a contract between us and a financial institution acting as trustee on behalf of the purchasers of the debt securities. We have entered into an indenture with U.S. Bank National Association, as trustee (the “indenture”), which is subject to the Trust Indenture Act of 1939. The trustee under the indenture has the following two main roles:

• the trustee can enforce your rights against us if we default; there are some limitations on the extent to which the trustee acts on your behalf, which are described later in this prospectus; and

• the trustee will perform certain administrative duties for us, which include sending you interest payments and notices.

As this section is a summary of some of the terms of the debt securities we may offer under this prospectus, it does not describe every aspect of the debt securities. We urge you to read the indenture and the other documents we file with the SEC relating to the debt securities because the indenture for those securities and those other documents, and not this description, will define your rights as a holder of our debt securities. We filed a copy of the indenture with the SEC as an exhibit to our Current Report on Form 8-K filed March 26, 2009, and it is incorporated in this prospectus by reference. We may file any such other documents as exhibits to an annual, quarterly or current report that we file with the SEC following their execution. See “Where You Can Find More Information” for information on how to obtain copies of the indenture and any such other documents. References to the “indenture” mean the indenture that will define your rights as a holder of debt securities. Capitalized terms used in this section and not otherwise defined have the meanings set forth in the indenture.

General

The debt securities will be our unsecured obligations. Senior debt securities will rank equally with all of our other unsecured and unsubordinated indebtedness. Subordinated debt securities will rank junior to our senior indebtedness, including our credit facilities.

You should read the prospectus supplement that will describe the following terms of the series of debt securities offered by the prospectus supplement:

• the title of the debt securities and whether the debt securities will be senior debt securities or subordinated debt securities;

• the ranking of the debt securities;

• if the debt securities are subordinated, the terms of subordination;

• the aggregate principal amount of the debt securities, the percentage of their principal amount at which the debt securities will be issued, and the date or dates when the principal of the debt securities will be payable or how those dates will be determined or extended;

• the interest rate or rates, which may be fixed or variable, that the debt securities will bear, if any, how the rate or rates will be determined, and the periods when the rate or rates will be in effect;

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• the date or dates from which any interest will accrue or how the date or dates will be determined, the date or dates on which any interest will be payable, whether and the terms under which payment of interest may be deferred, any regular record dates for these payments or how these dates will be determined and the basis on which any interest will be calculated, if other than on the basis of a 360-day year of twelve 30-day months;

• the place or places, if any, other than or in addition to New York City, of payment, transfer or exchange of the debt securities, and where notices or demands to or upon us in respect of the debt securities may be served;

• any optional redemption provisions and any restrictions on the sources of funds for redemption payments, which may benefit the holders of other securities;

• any sinking fund or other provisions that would obligate us to repurchase or redeem the debt securities;

• whether the amount of payments of principal of, any premium on, or interest on the debt securities will be determined with reference to an index, formula or other method, which could be based on one or more commodities, equity indices or other indices, and how these amounts will be determined;

• any modifications, deletions or additions to the events of default or covenants with respect to the debt securities described in this prospectus;

• if not the principal amount of the debt securities, the portion of the principal amount that will be payable upon acceleration of the maturity of the debt securities or how that portion will be determined;

• any modifications, deletions or additions to the provisions concerning defeasance and covenant defeasance contained in the indenture that will be applicable to the debt securities;

• any provisions granting special rights to the holders of the debt securities upon the occurrence of specified events;

• if other than the trustee, the name of the paying agent, security registrar or transfer agent for the debt securities;

• if we do not issue the debt securities in book-entry form only to be held by The Depository Trust Company, as depository, whether we will issue the debt securities in certificated form or the identity of any alternative depository;

• the person to whom any interest in a debt security will be payable, if other than the registered holder at the close of business on the regular record date;

• the denomination or denominations in which the debt securities will be issued, if other than denominations of $2,000 or any integral multiple of $1,000 in excess thereof;

• any provisions requiring us to pay Additional Amounts on the debt securities to any holder who is not a United States person in respect of any tax, assessment or governmental charge and, if so, whether we will have the option to redeem the debt securities rather than pay the Additional Amounts;

• whether the debt securities will be convertible into or exchangeable for other debt securities or common shares, and, if so, the terms and conditions upon which the debt securities will be so convertible or exchangeable, including the initial conversion or exchange price or rate or the method of calculation, how and when the conversion price or exchange ratio may be adjusted, whether conversion or exchange is mandatory, at the option of the holder or at our option, the conversion or exchange period and any other provision related to the debt securities; and

• any other material terms of the debt securities or the indenture, which may not be consistent with the terms set forth in this prospectus.

For purposes of this prospectus, any reference to the payment of principal of, any premium on, or interest on the debt securities will include Additional Amounts if required by the terms of the debt securities.

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The indenture does not limit the amount of debt securities that we are authorized to issue from time to time. The indenture also provides that there may be multiple series of debt securities issued thereunder and more than one trustee thereunder, each for one or more series of debt securities. If a trustee is acting under the indenture with respect to more than one series of debt securities, the debt securities for which it is acting would be treated as if issued under separate indentures. If there is more than one trustee under the indenture, the powers and trust obligations of each trustee will apply only to the debt securities of the separate series for which it is trustee.

We may issue debt securities with terms different from those of debt securities already issued. Without the consent of the holders of the outstanding debt securities, we may reopen a previous issue of a series of debt securities and issue additional debt securities of that series unless the reopening was restricted when we created that series.

There is no requirement that we issue debt securities in the future under the indenture, and we may use other indentures or documentation, containing different provisions in connection with future issues of other debt securities.

We may issue the debt securities as “original issue discount securities,” which are debt securities, including any zero-coupon debt securities that are issued and sold at a discount from their stated principal amount. Original issue discount securities provide that, upon acceleration of their maturity, an amount less than their principal amount will become due and payable. We will describe the U.S. federal income tax consequences and other considerations applicable to original issue discount securities in any prospectus supplement relating to them.

Holders of Debt Securities

Book-Entry Holders. We will issue debt securities in book-entry form only, unless we specify otherwise in the applicable prospectus supplement. This means the debt securities will be represented by one or more global securities registered in the name of a financial institution that holds them as depository on behalf of other financial institutions that participate in the depository’s book-entry system. These participating institutions, in turn, hold beneficial interests in the debt securities on behalf of themselves or their customers.

Under the indenture, we will recognize as a holder only the person in whose name a debt security is registered. Consequently, for debt securities issued in global form, we will recognize only the depository as the holder of the debt securities and we will make all payments on the debt securities to the depository. The depository passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depository and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the debt securities. As a result, you will not own the debt securities directly. Instead, you will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depository’s book-entry system or holds an interest through a participant. As long as the debt securities are issued in global form, you will be an indirect holder, and not a holder, of the debt securities.

Street Name Holders. In the future we may terminate a global security or issue debt securities initially in non-global form. In these cases, you may choose to hold your debt securities in your own name or in “street name.” Debt securities held in street name would be registered in the name of a bank, broker or other financial institution that you choose, and you would hold only a beneficial interest in those debt securities through an account you maintain at that institution.

For debt securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the debt securities are registered as the holders of those debt securities, and we will make all payments on those debt securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. If you hold debt securities in street name you will be an indirect holder, and not a holder, of those debt securities.

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Legal Holders. Our obligations, as well as the obligations of the trustee and those of any third parties employed by us or the trustee, run only to the legal holders of the debt securities. We do not have obligations to you if you hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether you choose to be an indirect holder of a debt security or have no choice because we are issuing the debt securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice, even if that holder is required, under agreements with depository participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, if we want to obtain the approval of the holders for any purpose (for example, to amend the indenture or to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture) we would seek the approval only from the holders, and not the indirect holders, of the debt securities. Whether and how the holders contact the indirect holders is up to the holders.

When we refer to you, we mean those who invest in the debt securities being offered by this prospectus, whether they are the holders or only indirect holders of those debt securities. When we refer to your debt securities, we mean the debt securities in which you hold a direct or indirect interest.

Special Considerations for Indirect Holders. If you hold debt securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

• how it handles securities payments and notices;

• whether it imposes fees or charges;

• how it would handle a request for the holders’ consent, if ever required;

• whether and how you can instruct it to send you debt securities registered in your own name so you can be a holder, if that is permitted in the future;

• how it would exercise rights under the debt securities if there were a default or other event triggering the need for holders to act to protect their interests; and

• if the debt securities are in book-entry form, how the depository’s rules and procedures will affect these matters.

Global Securities

What is a Global Security? We will issue each debt security under the indenture in book-entry form only, unless we specify otherwise in the applicable prospectus supplement. A global security represents one or any other number of individual debt securities. Generally, all debt securities represented by the same global securities will have the same terms. We may, however, issue a global security that represents multiple debt securities that have different terms and are issued at different times. We call this kind of global security a master global security.

Each debt security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depository. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will be the depository for all debt securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depository or its nominee, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depository, or its

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nominee, will be the sole registered owner and holder of all debt securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depository or with another institution that does. Thus, if your security is represented by a global security, you will not be a holder of the debt security, but only an indirect holder of a beneficial interest in the global security.

Special Considerations for Global Securities. We do not recognize an indirect holder as a holder of debt securities and instead deal only with the depository that holds the global security. The account rules of your financial institution and of the depository, as well as general laws relating to securities transfers, will govern your rights relating to a global security.

If we issue debt securities only in the form of a global security, you should be aware of the following:

• you cannot cause the debt securities to be registered in your name, and cannot obtain non-global certificates for your interest in the debt securities, except in the special situations that we describe below;

• you will be an indirect holder and must look to your own bank or broker for payments on the debt securities and protection of your legal rights relating to the debt securities, as we describe under “Holders of Debt Securities” above;

• you may not be able to sell interests in the debt securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

• you may not be able to pledge your interest in a global security in circumstances where certificates representing the debt securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

• the depository’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to your interest in a global security. We and the trustee have no responsibility for any aspect of the depository’s actions or for its records of ownership interests in a global security. We and the trustee also do not supervise the depository in any way;

• DTC requires, and other depositories may require, that those who purchase and sell interests in a global security within its book-entry system use immediately available funds and your broker or bank may require you to do so as well; and

• financial institutions that participate in the depository’s book-entry system, and through which you hold your interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the debt security. Your chain of ownership may contain more than one financial intermediary. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When a Global Security Will Be Terminated. In a few special situations described below, a global security will be terminated and interests in it will be exchanged for certificates in non-global form representing the debt securities it represented. After that exchange, you will be able to choose whether to hold the debt securities directly or in street name. You must consult your own bank or broker to find out how to have your interests in a global security transferred on termination to your own name, so that you will be a holder. We have described the rights of holders and street name investors above under “Holders of Debt Securities.”

The special situations for termination of a global security are as follows:

• if the depository notifies us that it is unwilling, unable or no longer qualified to continue as depository for that global security and we do not appoint another institution to act as depository within 60 days;

• if we notify the trustee that we wish to terminate that global security; or

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• if an event of default has occurred with regard to debt securities represented by that global security and has not been cured or waived. We discuss defaults later under “Events of Default.”

If a global security is terminated, only the depository, and not we or the trustee, is responsible for deciding the names of the intermediary banks, brokers and other financial institutions in whose names the debt securities represented by the global security are registered, and, therefore, who will be the holders of those debt securities.

Covenants

This section summarizes the material covenants in the indenture. Please refer to the applicable prospectus supplement for information about any changes to our covenants, including any addition or deletion of a covenant, and to the indenture for information on other covenants not described in this prospectus or the applicable prospectus supplement.

Limitations on Liens. We covenant in the indenture that we will not, and will not permit any of our Restricted Subsidiaries to, create, incur, issue or assume any Indebtedness secured by any Lien on any Principal Property, or on shares of stock or Indebtedness of any Restricted Subsidiary, known as Restricted Securities, without making effective provision for the Outstanding Securities, other than debt securities of any series not entitled to the benefit of this covenant, to be secured by a Lien equally and ratably with, or prior to (or in the case of debt securities of any series that are subordinated in right of payment to the Indebtedness secured by such Lien, by a Lien subordinated to), the Lien securing such Indebtedness for so long as the Indebtedness is so secured, except that the foregoing restriction does not apply to:

• any Lien existing on the date of the first issuance of debt securities of the relevant series under the indenture or existing on such other date as may be specified in any supplemental indenture, board resolution or officers’ certificate with respect to such series;

• any Lien on any Principal Property or Restricted Securities of any person existing at the time that person is merged or consolidated with or into us or a Restricted Subsidiary, or this person becomes a Restricted Subsidiary, or arising thereafter otherwise than in connection with the borrowing of money arranged thereafter and pursuant to contractual commitments entered into prior to and not in contemplation of the person’s becoming a Restricted Subsidiary;

• any Lien on any Principal Property or Restricted Securities existing at the time we or a Restricted Subsidiary acquire the Principal Property or Restricted Securities, whether or not the Lien is assumed by us or the Restricted Subsidiary, provided that this Lien may not extend to any other Principal Property or Restricted Securities of ours or any Restricted Subsidiary;

• any Lien on any Principal Property, including any improvements on any existing Principal Property, of ours or any Restricted Subsidiary, and any Lien on Restricted Securities of a Restricted Subsidiary that was formed or is held for the purpose of acquiring and holding the Principal Property, in each case to secure all or any part of the cost of acquisition, development, operation, construction, alteration, repair or improvement of all or any part of the Principal Property, or to secure Indebtedness incurred by us or a Restricted Subsidiary for the purpose of financing all or any part of that cost, provided that the Lien is created prior to, at the time of, or within 12 months after the latest of, the acquisition, completion of construction or improvement or commencement of commercial operation of that Principal Property and, provided further, that the Lien may not extend to any other Principal Property of ours or any Restricted Subsidiary, other than any currently unimproved real property on which the Principal Property has been constructed or developed or the improvement is located;

• any Lien on any Principal Property or Restricted Securities to secure Indebtedness owed to us or to a Restricted Subsidiary;

• any Lien in favor of a governmental body to secure advances or other payments under any contract or statute or to secure Indebtedness incurred to finance the purchase price or cost of constructing or improving the property subject to the Lien;

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• any Lien created in connection with a project financed with, and created to secure, Non-Recourse Indebtedness;

• any extension, renewal, substitution or replacement, or successive extensions, renewals, substitutions or replacements, in whole or in part, of any Lien referred to in any of the bullet points above, provided that the Indebtedness secured may not exceed the principal amount of Indebtedness that is secured at the time of the renewal or refunding, plus any premium, cost or expense in connection with such extensions, renewals, substitutions or replacements, and that the renewal or refunding Lien must be limited to all or any part of the same property and improvements, shares of stock or Indebtedness that secured the Lien that was renewed or refunded; or

• any Lien not permitted above securing Indebtedness that, together with the aggregate outstanding principal amount of other secured Indebtedness that would otherwise be subject to the above restrictions, excluding Indebtedness secured by Liens permitted under the above exceptions, and the Attributable Debt in respect of all Sale and Leaseback Transactions, not including Attributable Debt in respect of any Sale and Leaseback Transactions described in the last two bullet points in the next succeeding paragraph, would not then exceed 15% of our Consolidated Net Tangible Assets.

Limitation on Sale and Leaseback Transactions. We covenant in the indenture that we will not, and will not permit any Restricted Subsidiary to, enter into any Sale and Leaseback Transaction unless:

• we or a Restricted Subsidiary would be entitled, without securing the Outstanding Securities of any series, to incur Indebtedness secured by a Lien on the Principal Property that is the subject of the Sale and Leaseback Transaction;

• the Attributable Debt associated with the Sale and Leaseback Transaction would be in an amount permitted under the last bullet point of the preceding paragraph;

• the proceeds received in respect of the Principal Property so sold and leased back at the time of entering into the Sale and Leaseback Transaction are to be used for our business and operations or the business and operations of any Subsidiary; or

• within 12 months after the sale or transfer, an amount equal to the proceeds received in respect of the Principal Property sold and leased back at the time of entering into the Sale and Leaseback Transaction is applied to the prepayment, other than mandatory prepayment, of any Outstanding Securities or Funded Indebtedness owed by us or a Restricted Subsidiary, other than Funded Indebtedness that is held by us or any Restricted Subsidiary or our Funded Indebtedness that is subordinate in right of payment to any Outstanding Securities that are entitled to the benefit of this covenant.

Definitions. Following are definitions of some of the terms used in the covenants described above.

“Attributable Debt” means, as to any lease under which a person is at the time liable for rent, at a date that liability is to be determined, the total net amount of rent required to be paid by that person under the lease during the remaining term, excluding amounts required to be paid on account of maintenance and repairs, services, insurance, taxes, assessments, water rates and similar charges and contingent rents, discounted from the respective due dates thereof at the rate of interest (or Yield to Maturity, in the case of original issue discount securities) borne by the then Outstanding Securities, compounded monthly.

“Capital Stock” means any and all shares, interests, rights to purchase, warrants, options, participations or other equivalents of or interests, however designated, in stock issued by a corporation.

“Consolidated Net Tangible Assets” means the aggregate amount of assets, less applicable reserves and other properly deductible items, after deducting:

• all current liabilities, excluding any portion thereof constituting Funded Indebtedness; and

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• all goodwill, trade names, trademarks, patents, unamortized debt discount and expense and other like intangibles,

all as set forth on our most recent consolidated balance sheet contained in our latest quarterly or annual report filed with the SEC under the Securities Exchange Act of 1934, as amended, and computed in accordance with generally accepted accounting principles.

“Funded Indebtedness” means, as applied to any person, all Indebtedness of such person maturing after, or renewable or extendible at the option of the person beyond, 12 months from the date of determination.

“Indebtedness” means obligations for money borrowed, evidenced by notes, bonds, debentures or other similar evidences of indebtedness.

“Lien” means any lien, mortgage, pledge, encumbrance, charge or security interest securing Indebtedness; provided, however, that the following types of transactions will not be considered, for purposes of this definition, to result in a Lien:

• any acquisition by us or any Restricted Subsidiary of any property or assets subject to any reservation or exception under the terms of which any vendor, lessor or assignor creates, reserves or excepts or has created, reserved or excepted an interest in oil, gas or any other mineral in place or the proceeds of that interest;

• any conveyance or assignment whereby we or any Restricted Subsidiary conveys or assigns to any person or persons an interest in oil, gas or any other mineral in place or the proceeds of that interest;

• any Lien upon any property or assets either owned or leased by us or a Restricted Subsidiary or in which we or any Restricted Subsidiary owns an interest that secures for the benefit of the person or persons paying the expenses of developing or conducting operations for the recovery, storage, transportation or sale of the mineral resources of the property or assets, or property or assets with which it is unitized, the payment to such person or persons of our proportionate part or the Restricted Subsidiary’s proportionate part of the development or operating expenses;

• any lease classified as an operating lease under generally accepted accounting principles;

• any hedging arrangements entered into in the ordinary course of business, including any obligation to deliver any mineral, commodity or asset in connection therewith; or

• any guarantees that we make for the repayment of Indebtedness of any Subsidiary or guarantees by any Subsidiary of the repayment of Indebtedness of any entity, including Indebtedness of Atmos Energy Marketing, LLC.

“Non-Recourse Indebtedness” means, at any time, Indebtedness incurred after the date of the indenture by us or a Restricted Subsidiary in connection with the acquisition of property or assets by us or a Restricted Subsidiary or the financing of the construction of or improvements on property, whenever acquired, provided that, under the terms of this Indebtedness and under applicable law, the recourse at the time and thereafter of the lenders with respect to this Indebtedness is limited to the property or assets so acquired, or the construction or improvements, including Indebtedness as to which a performance or completion guarantee or similar undertaking was initially applicable to the Indebtedness or the related property or assets if the guarantee or similar undertaking has been satisfied and is no longer in effect. Indebtedness which is otherwise Non-Recourse Indebtedness will not lose its character as Non-Recourse Indebtedness because there is recourse to us, any subsidiary of ours or any other person for (a) environmental or tax warranties and indemnities and such other representations, warranties, covenants and indemnities as are customarily required in such transactions or (b) indemnities for and liabilities arising from fraud, misrepresentation, misapplication or non-payment of rents, profits, insurance and condemnation proceeds and other sums actually received from secured assets to be paid to the lender, waste and mechanics’ liens or similar matters.

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“Principal Property” means any natural gas distribution property located in the United States, except any property that in the opinion of our board of directors is not of material importance to the total business conducted by us and of our consolidated Subsidiaries.

“Restricted Subsidiary” means any Subsidiary the amount of Consolidated Net Tangible Assets of which constitutes more than 10% of the aggregate amount of Consolidated Net Tangible Assets of us and our Subsidiaries.

“Sale and Leaseback Transaction” means any arrangement with any person in which we or any Restricted Subsidiary leases any Principal Property that has been or is to be sold or transferred by us or the Restricted Subsidiary to that person, other than any such arrangement involving:

• a lease for a term, including renewals at the option of the lessee, of not more than three years or classified as an operating lease under generally accepted accounting principles;

• leases between us and a Restricted Subsidiary or between Restricted Subsidiaries; and

• leases of a Principal Property executed by the time of, or within 12 months after the latest of, the acquisition, the completion of construction or improvement, or the commencement of commercial operation, of the Principal Property, whichever is later.

“Subsidiary” of ours means:

• a corporation, a majority of whose Capital Stock with rights, under ordinary circumstances, to elect directors is owned, directly or indirectly, at the date of determination, by us, by one or more of our Subsidiaries or by us and one or more of our Subsidiaries; or

• any other person, other than a corporation, in which at the date of determination we, one or more of our Subsidiaries or we and one or more of our Subsidiaries, directly or indirectly, have at least a majority ownership and power to direct the policies, management and affairs of that person.

Consolidation, Merger or Sale of Assets. Under the terms of the indenture, we will be generally permitted to consolidate with or merge into another entity. We will also be permitted to sell or transfer our assets substantially as an entirety to another entity. However, we may not take any of these actions unless all of the following conditions are met:

• the resulting entity, or the person to which such assets will have been sold or transferred, must agree to be legally responsible for all our obligations relating to the debt securities and the indenture;

• the transaction must not cause a default or an Event of Default, or an event that with notice or lapse of time or both would become an Event of Default, as described below;

• the resulting entity, or the person to which such assets will have been sold or transferred, must be organized under the laws of the United States or one of the states or the District of Columbia; and

• we must deliver an officers’ certificate and legal opinion to the trustee with respect to the transaction.

In the event that we engage in one of these transactions and comply with the conditions listed above, we would be discharged from all our obligations and covenants under the indenture and all obligations under the Outstanding Securities, with the successor corporation or person succeeding to our obligations and covenants.

In the event that we engage in one of these transactions, the indenture provides that, if any Principal Property or Restricted Securities would thereupon become subject to any Lien securing the Indebtedness, the debt securities, other than debt securities not entitled to the benefits of specified covenants, must be secured, as to such Principal Property or Restricted Securities, equally and ratably with (or prior to or, in the case of debt

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securities that are subordinated in right of payment to the Indebtedness secured by such Lien or in the case of other Indebtedness of ours that is subordinated to the debt securities, on a subordinated basis to such Lien securing) the Indebtedness or obligations that upon the occurrence of such transaction would become secured by the Lien, unless the Lien could be created under the indenture without equally and ratably securing the debt securities (or, in the case of debt securities that are subordinated in right of payment to the Indebtedness secured by such Lien, on a subordinated basis to such Lien).

Modification or Waiver

There are two types of changes that we can make to the indenture and the debt securities.

Changes Requiring Approval. With the approval of the holders of at least a majority in principal amount of all outstanding debt securities of each series affected (including any such approvals obtained in connection with a tender or exchange offer for outstanding debt securities), we may make any changes, additions or deletions to any provisions of the indenture applicable to the affected series, or modify the rights of the holders of the debt securities of the affected series. However, without the consent of each holder affected, we cannot:

• change the stated maturity of the principal of, any premium on, or the interest on a debt security;

• reduce the principal amount, any premium on, or the rate of interest on a debt security;

• change any of our obligations to pay Additional Amounts;

• reduce the amount payable upon acceleration of maturity following the default of a debt security whose principal amount payable at stated maturity may be more or less than its principal face amount at original issuance or an original issue discount security;

• adversely affect any right of repayment at the holder’s option;

• change the place of payment of a debt security;

• impair the holder’s right to sue for payment;

• adversely affect any right to convert or exchange a debt security;

• reduce the percentage of holders of debt securities whose consent is needed to modify or amend the indenture; or

• modify certain provisions of the indenture dealing with suits for enforcement of payment by the trustee or modification and waiver, except to increase any percentage of consents required to amend the indenture or for any waiver, or to modify the provisions of the indenture dealing with the unconditional right of the holders of the debt securities to receive principal, premium, if any, and interest.

Changes Not Requiring Approval. The second type of change does not require any vote by the holders of the debt securities. This type is limited to clarifications and certain other changes that would not adversely affect holders of the outstanding debt securities in any material respect. Additionally, we do not need any approval to make any change that affects only debt securities to be issued under the indenture after the changes take effect.

Further Details Concerning Voting. When taking a vote, we will use the following rules to decide how much principal amount to attribute to a debt security:

• for original issue discount securities, we will use the principal amount that would be due and payable on the voting date if the maturity of the debt securities were accelerated to that date because of a default; and

• for debt securities whose principal amount is not known (for example, because it is based on an index) we will use a special rule for that debt security described in the applicable prospectus supplement.

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Debt securities will not be considered outstanding, and therefore not eligible to vote, if we have deposited or set aside in trust money for their payment or redemption. Debt securities will also not be eligible to vote if they have been fully defeased as described later under “Defeasance and Covenant Defeasance.”

Book-entry and other indirect holders should consult their banks or brokers for information on how approval may be granted or denied if we seek to change the indenture or the debt securities or request a waiver.

Events of Default

Holders of debt securities will have special rights if an Event of Default occurs as to the debt securities of their series that is not cured, as described later in this subsection. Please refer to the applicable prospectus supplement for information about any changes to the Events of Default, including any addition of a provision providing event risk or similar protection.

What is an Event of Default? The term “Event of Default” as to the debt securities of a series means any of the following:

• we do not pay interest on a debt security of the series within 30 days of its due date;

• we do not pay the principal of or any premium, if any, on a debt security of the series at its maturity;

• we do not deposit any sinking fund payment when and as due by the terms of any debt securities requiring such payment;

• we remain in breach of a covenant or agreement in the indenture, other than a covenant or agreement not for the benefit of the series, for 60 days after we receive written notice stating that we are in breach from the trustee or the holders of at least 25 percent of the principal amount of the debt securities of the series;

• we or a Restricted Subsidiary is in default under any matured or accelerated agreement or instrument under which we have outstanding Indebtedness for borrowed money or guarantees, which individually is in excess of $25,000,000, and we have not cured any acceleration within 30 days after we receive notice of this default from the trustee or the holders of at least 25 percent of the principal amount of the debt securities of the series, unless prior to the entry of judgment for the trustee, we or the Restricted Subsidiary remedy the default or the default is waived by the holders of the indebtedness;

• we file for bankruptcy or other events of bankruptcy, insolvency or reorganization occur; or

• any other Event of Default provided for the benefit of debt securities of the series.

An Event of Default for a particular series of debt securities will not necessarily constitute an Event of Default for any other series of debt securities issued under the indenture.

The trustee may withhold notice to the holders of debt securities of a particular series of any default if it considers its withholding of notice to be in the interest of the holders of that series, except that the trustee may not withhold notice of a default in the payment of the principal of, any premium on, or the interest on the debt securities or in the payment of any sinking fund installment with respect to the debt securities.

Remedies if an Event of Default Occurs. If an event of default has occurred and is continuing, the trustee or the holders of at least 25 percent in principal amount of the debt securities of the affected series may declare the entire principal amount and all accrued interest of all the debt securities of that series to be due and immediately payable by notifying us, and the trustee, if the holders give notice, in writing. This is called a declaration of acceleration of maturity.

If the maturity of any series of debt securities is accelerated and a judgment for payment has not yet been obtained, the holders of a majority in principal amount of the debt securities of that series may cancel the

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acceleration if all events of default other than the non-payment of principal or interest on the debt securities of that series that have become due solely by a declaration of acceleration are cured or waived, and we deposit with the trustee a sufficient sum of money to pay:

• all overdue interest on outstanding debt securities of that series;

• all unpaid principal and any premium, if any, of any outstanding debt securities of that series that has become due otherwise than by a declaration of acceleration, and interest on the unpaid principal and any premium, if any;

• all interest on such overdue interest; and

• all amounts paid or advanced by the trustee for that series and reasonable compensation of the trustee.

Except in cases of default, where the trustee has some special duties, the trustee is not required to take any action under the indenture at the request of any holders unless the holders offer the trustee reasonable protection from expenses and liability. This is called an indemnity. If reasonable indemnity is provided, the holders of a majority in principal amount of the outstanding debt securities of the relevant series may direct the time, method and place of conducting any lawsuit or other formal legal action seeking any remedy available to the trustee. The trustee may refuse to follow those directions if the directions conflict with any law or the indenture or expose the trustee to personal liability. No delay or omission in exercising any right or remedy will be treated as a waiver of that right, remedy or Event of Default.

Before a holder is allowed to bypass the trustee and bring his or her own lawsuit or other formal legal action or take other steps to enforce his or her rights or protect his or her interest relating to the debt securities, the following must occur:

• the holder must give the trustee written notice that an Event of Default has occurred and remains uncured;

• the holders of at least 25 percent in principal amount of all outstanding debt securities of the relevant series must make a written request that the trustee take action because of the default and must offer reasonable indemnity to the trustee against the cost and other liabilities of taking that action;

• the trustee must not have instituted a proceeding for 60 days after receipt of the above notice and offer of indemnity; and

• the holders of a majority in principal amount of the debt securities must not have given the trustee a direction inconsistent with the above notice during the 60-day period.

However, a holder is entitled at any time to bring a lawsuit for the payment of money due on his or her debt securities on or after the due date without complying with the foregoing.

Holders of a majority in principal amount of the debt securities of the affected series may waive any past defaults other than the following:

• the payment of principal, any premium, or interest on any debt security; or

• in respect of a covenant that under the indenture cannot be modified or amended without the consent of each holder affected.

Each year, we will furnish the trustee with a written statement of two of our officers certifying that, to their knowledge, we are in compliance with the indenture and the debt securities, or else specifying any default.

Book-entry and other indirect holders should consult their banks or brokers for information on how to give notice or direction to or make a request of the trustee and how to declare or cancel an acceleration.

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Defeasance and Covenant Defeasance

Unless we provide otherwise in the applicable prospectus supplement, the provisions for full defeasance and covenant defeasance described below apply to each series of debt securities. In general, we expect these provisions to apply to each debt security that is not a floating rate or indexed debt security.

Full Defeasance. If there is a change in U.S. federal tax law, as described below, we can legally release ourselves from all payment and other obligations on the debt securities, called “full defeasance,” if we put in place the following arrangements for you to be repaid:

• we must deposit in trust for the benefit of all holders of the debt securities a combination of money and obligations issued or guaranteed by the U.S. government that will generate enough cash to make interest, principal and any other payments on the debt securities on their various due dates; and

• we must deliver to the trustee a legal opinion confirming that there has been a change in current federal tax law or an IRS ruling that lets us make the above deposit without causing you to be taxed on the debt securities any differently than if we did not make the deposit and just repaid the debt securities ourselves at maturity.

If we ever did accomplish defeasance, as described above, you would have to rely solely on the trust deposit for repayment of the debt securities. You could not look to us for repayment in the event of any shortfall. Conversely, the trust deposit would most likely be protected from claims of our lenders and other creditors if we ever become bankrupt or insolvent. If we accomplish a defeasance, we would retain only the obligations to register the transfer or exchange of the debt securities, to maintain an office or agency in respect of the debt securities and to hold moneys for payment in trust.

Covenant Defeasance. Under current federal tax law, we can make the same type of deposit described above and be released from any restrictive covenants in the indenture. This is called “covenant defeasance.” In that event, you would lose the protection of any such covenants but would gain the protection of having money and obligations issued or guaranteed by the U.S. government set aside in trust to repay the debt securities. In order to achieve covenant defeasance, we must do the following:

• deposit in trust for your benefit and the benefit of all other direct holders of the debt securities a combination of money and obligations issued or guaranteed by the U.S. government that will generate enough cash to make interest, principal and any other payments on the debt securities on their various due dates; and

• deliver to the trustee a legal opinion of our counsel confirming that, under current federal income tax law, we may make the deposit described above without causing you to be taxed on the debt securities any differently than if we did not make the deposit and just repaid the debt securities ourselves at maturity.

If we accomplish covenant defeasance, you can still look to us for repayment of the debt securities if there were a shortfall in the trust deposit or the trustee is prevented from making payment. In fact, if one of the remaining Events of Default occurred, such as our bankruptcy, and the debt securities became immediately due and payable, there may be a shortfall. Depending on the event causing the default, you may not be able to obtain payment of the shortfall.

Debt Securities Issued in Non-Global Form

If any debt securities cease to be issued in global form, they will be issued:

• only in fully registered form;

• without interest coupons; and

• unless we indicate otherwise in the prospectus supplement, in denominations of $2,000 and amounts that are integral multiples of $1,000 in excess thereof.

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Holders may exchange their debt securities that are not in global form for debt securities of smaller denominations or combined into fewer debt securities of larger denominations, as long as the total principal amount is not changed.

Holders may exchange or transfer their debt securities at the office of the trustee. We may appoint the trustee to act as our agent for registering debt securities in the names of holders transferring debt securities, or we may appoint another entity to perform these functions or perform them ourselves.

Holders will not be required to pay a service charge to transfer or exchange their debt securities, but they may be required to pay for any tax or other governmental charge associated with the transfer or exchange. The transfer or exchange will be made only if our transfer agent is satisfied with the holder’s proof of legal ownership.

If we have designated additional transfer agents for a holder’s debt security, they will be named in the applicable prospectus supplement. We may appoint additional transfer agents or cancel the appointment of any particular transfer agent. We may also approve a change in the office through which any transfer agent acts.

If any debt securities are redeemable and we redeem less than all those debt securities, we may stop the transfer or exchange of those debt securities during the period beginning 15 days before the day we mail the notice of redemption and ending on the day of that mailing, in order to freeze the list of holders to prepare the mailing. We may also refuse to register transfers or exchanges of any debt securities selected for redemption, except that we will continue to permit transfers and exchanges of the unredeemed portion of any debt security that will be partially redeemed.

If a debt security is issued as a global security, only the depository will be entitled to transfer and exchange the debt security as described in this section, since it will be the sole holder of the debt security.

Payment Mechanics

Who Receives Payment? If interest is due on a debt security on an interest payment date, we will pay the interest to the person or entity in whose name the debt security is registered at the close of business on the regular record date, discussed below, relating to the interest payment date. If interest is due at maturity but on a day that is not an interest payment date, we will pay the interest to the person or entity entitled to receive the principal of the debt security. If principal or another amount besides interest is due on a debt security at maturity, we will pay the amount to the holder of the debt security against surrender of the debt security at a proper place of payment, or, in the case of a global security, in accordance with the applicable policies of the depository.

Payments on Global Securities. We will make payments on a global security in accordance with the applicable policies of the depository as in effect from time to time. Under those policies, we will pay directly to the depository, or its nominee, and not to any indirect holders who own beneficial interests in the global security. An indirect holder’s right to those payments will be governed by the rules and practices of the depository and its participants, as described above under “What is a Global Security?”.

Payments on Non-Global Securities. For a debt security in non-global form, we will pay interest that is due on an interest payment date by check mailed on the interest payment date to the holder at his or her address shown on the trustee’s records as of the close of business on the regular record date. We will make all other payments by check, at the paying agent described below, against surrender of the debt security. We will make all payments by check in next-day funds; for example, funds that become available on the day after the check is cashed.

Alternatively, if a non-global security has a face amount of at least $1,000,000 and the holder asks us to do so, we will pay any amount that becomes due on the debt security by wire transfer of immediately available funds to an account at a bank in New York City on the due date. To request wire payment, the holder must give

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the paying agent appropriate transfer instructions at least five business days before the requested wire payment is due. In the case of any interest payment due on an interest payment date, the instructions must be given by the person who is the holder on the relevant regular record date. In the case of any other payment, we will make payment only after the debt security is surrendered to the paying agent. Any wire instructions, once properly given, will remain in effect unless and until new instructions are given in the manner described above.

Regular Record Dates. We will pay interest to the holders listed in the trustee’s records as the owners of the debt securities at the close of business on a particular day in advance of each interest payment date. We will pay interest to these holders if they are listed as the owner even if they no longer own the debt security on the interest payment date. That particular day, usually about two weeks in advance of the interest payment date, is called the “regular record date” and will be identified in the prospectus supplement.

Payment When Offices Are Closed. If any payment is due on a debt security on a day that is not a business day, we will make the payment on the next business day. Payments postponed to the next business day in this situation will be treated under the indenture as if they were made on the original due date. A postponement of this kind will not result in a default under any debt security or the indenture, and no interest will accrue on the postponed amount from the original due date to the next business day.

Paying Agents. We may appoint one or more financial institutions to act as our paying agents, at whose designated offices debt securities in non-global form may be surrendered for payment at their maturity. We call each of those offices a paying agent. We may add, replace or terminate paying agents from time to time. We may also choose to act as our own paying agent. Initially, we have appointed the trustee, at its corporate trust office in New York City, as the paying agent. We must notify you of changes in the paying agents.

Book-entry and other indirect holders should consult their banks or brokers for information on how they will receive payments on their debt securities.

The Trustee Under the Indenture

U.S. Bank National Association is the trustee under the indenture for our debt securities. We will identify any other entity acting as the trustee for a series of debt securities that we may offer in the prospectus supplement for the offering of such debt securities.

The trustee may resign or be removed with respect to one or more series of debt securities and a successor trustee may be appointed to act with respect to these series.

DESCRIPTION OF COMMON STOCK

General

Our authorized capital stock consists of 200,000,000 shares of common stock, of which 90,538,115 shares were outstanding on March 26, 2013. Each of our shares of common stock is entitled to one vote on all matters voted upon by shareholders. Our shareholders do not have cumulative voting rights. Our issued and outstanding shares of common stock are fully paid and nonassessable. There are no redemption or sinking fund provisions applicable to the shares of our common stock, and such shares are not entitled to any preemptive rights. Since we are incorporated in both Texas and Virginia, we must comply with the laws of both states when issuing shares of our common stock.

Holders of our shares of common stock are entitled to receive such dividends as may be declared from time to time by our board of directors from our assets legally available for the payment of dividends and, upon our liquidation, a pro rata share of all of our assets available for distribution to our shareholders.

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American Stock Transfer & Trust Company is the registrar and transfer agent for our common stock.

Charter and Bylaws Provisions

Some provisions of our articles of incorporation and bylaws may be deemed to have an “anti-takeover” effect. The following description of these provisions is only a summary, and we refer you to our articles of incorporation and bylaws for more information. Our articles of incorporation and bylaws are included as exhibits to our annual reports on Form 10-K filed with the SEC. See “Where You Can Find More Information.”

Cumulative Voting. Our articles of incorporation prohibit cumulative voting. In general, in the absence of cumulative voting, one or more persons who hold a majority of our outstanding shares can elect all of the directors who are subject to election at any meeting of shareholders.

Removal of Directors. Our articles of incorporation and bylaws also provide that our directors may be removed only for cause and upon the affirmative vote of the holders of at least 75 percent of the shares then entitled to vote at an election of directors.

Fair Price Provisions. Article VII of our articles of incorporation provides certain “Fair Price Provisions” for our shareholders. Under Article VII, a merger, consolidation, sale of assets, share exchange, recapitalization or other similar transaction, between us or a company controlled by or under common control with us and any individual, corporation or other entity which owns or controls 10 percent or more of our voting capital stock, would be required to satisfy the condition that the aggregate consideration per share to be received in the transaction for each class of our voting capital stock be at least equal to the highest per share price, or equivalent price for any different classes or series of stock, paid by the 10 percent shareholder in acquiring any of its holdings of our stock. If a proposed transaction with a 10 percent shareholder does not meet this condition, then the transaction must be approved by the holders of at least 75 percent of the outstanding shares of voting capital stock held by our shareholders other than the 10 percent shareholder, unless a majority of the directors who were members of our board immediately prior to the time the 10 percent shareholder involved in the proposed transaction became a 10 percent shareholder have either:

• expressly approved in advance the acquisition of the outstanding shares of our voting capital stock that caused the 10 percent shareholder to become a 10 percent shareholder; or

• approved the transaction either in advance of or subsequent to the 10 percent shareholder becoming a 10 percent shareholder.

The provisions of Article VII may not be amended, altered, changed, or repealed except by the affirmative vote of at least 75 percent of the votes entitled to be cast thereon at a meeting of our shareholders duly called for consideration of such amendment, alteration, change, or repeal. In addition, if there is a 10 percent shareholder, such action must also be approved by the affirmative vote of at least 75 percent of the outstanding shares of our voting capital stock held by the shareholders other than the 10 percent shareholder.

Shareholder Proposals and Director Nominations. Our shareholders can submit shareholder proposals and nominate candidates for the board of directors if the shareholders follow the advance notice procedures described in our bylaws.

Shareholder proposals (other than those sought to be included in our proxy statement) must be submitted to our corporate secretary at least 60 days, but not more than 85 days, before the annual meeting; provided, however, that if less than 75 days’ notice or prior public disclosure of the date of the annual meeting is given or made to shareholders, notice by the shareholder to be timely must be received by our corporate secretary no later than the close of business on the 25th day following the day on which such notice of the date of the annual meeting was provided or such public disclosure was made. The notice must include a description of the proposal, the shareholder’s name and address and the number of shares held, and all other information which would be

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required to be included in a proxy statement filed with the SEC if the shareholder were a participant in a solicitation subject to the SEC’s proxy rules. To be included in our proxy statement for an annual meeting, our corporate secretary must receive the proposal at least 120 days prior to the anniversary of the date we mailed the proxy statement for the prior year’s annual meeting.

To nominate directors, shareholders must submit a written notice to our corporate secretary at least 60 days, but not more than 85 days, before a scheduled meeting; provided, however, that if less than 75 days’ notice or prior public disclosure of the date of the annual meeting is given or made to shareholders, such nomination shall have been received by our corporate secretary no later than the close of business on the 25th day following the day on which such notice of the date of the annual meeting was mailed or such public disclosure was made. The notice must include the name and address of the shareholder and of the shareholder’s nominee, the number of shares held by the shareholder, a representation that the shareholder is a holder of record of common stock entitled to vote at the meeting, and that the shareholder intends to appear in person or by proxy to nominate the persons specified in the notice, a description of any arrangements between the shareholder and the shareholder’s nominee, information about the shareholder’s nominee required by the SEC and the written consent of the shareholder’s nominee to serve as a director.

Shareholder proposals and director nominations that are late or that do not include all required information may be rejected. This could prevent shareholders from bringing certain matters before an annual or special meeting or making nominations for directors.

PLAN OF DISTRIBUTION

We may sell the securities offered by this prospectus and a prospectus supplement as follows:

• through agents;

• to or through underwriters;

• through dealers;

• directly by us to purchasers; or

• through a combination of any such methods of sale.

We, directly or through agents or dealers, may sell, and the underwriters may resell, the securities in one or more transactions, including:

• transactions on the New York Stock Exchange or any other organized market where the securities may be traded;

• in the over-the-counter market;

• in negotiated transactions; or

• through a combination of any such methods of sale.

The securities may be sold at a fixed price or prices which may be changed, at market prices prevailing at the time of sale, at prices related to such prevailing market prices or at negotiated prices.

Agents designated by us from time to time may solicit offers to purchase the securities. We will name any such agent involved in the offer or sale of the securities and set forth any commissions payable by us to such agent in a prospectus supplement relating to any such offer and sale of securities. Unless otherwise indicated in the prospectus supplement, any such agent will be acting on a best efforts basis for the period of its appointment. Any such agent may be deemed to be an underwriter of the securities, as that term is defined in the Securities Act.

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If underwriters are used in the sale of securities, securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions. Securities may be offered to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. If an underwriter or underwriters are used in the sale of securities, we will execute an underwriting agreement with such underwriter or underwriters at the time an agreement for such sale is reached. We will set forth in the prospectus supplement the names of the specific managing underwriter or underwriters, as well as any other underwriters, and the terms of the transactions, including compensation of the underwriters and dealers. Such compensation may be in the form of discounts, concessions or commissions. Underwriters and others participating in any offering of securities may engage in transactions that stabilize, maintain or otherwise affect the price of such securities. We will describe any such activities in the prospectus supplement.

We may elect to list any class or series of securities on any exchange, but we are not currently obligated to do so. It is possible that one or more underwriters, if any, may make a market in a class or series of securities, but the underwriters will not be obligated to do so and may discontinue any market making at any time without notice. We cannot give any assurance as to the liquidity of the trading market for any of the securities we may offer.

If a dealer is used in the sale of the securities, we or an underwriter will sell such securities to the dealer, as principal. The dealer may then resell such securities to the public at varying prices to be determined by such dealer at the time of resale. The prospectus supplement will set forth the name of the dealer and the terms of the transactions.

We may directly solicit offers to purchase the securities, and we may sell directly to institutional investors or others. These persons may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale of the securities. The prospectus supplement will describe the terms of any such sales, including the terms of any bidding, auction or other process, if used.

Agents, underwriters and dealers may be entitled under agreements which may be entered into with us to indemnification by us against specified liabilities, including liabilities under the Securities Act, or to contribution by us to payments they may be required to make in respect of such liabilities. The prospectus supplement will describe the terms and conditions of such indemnification or contribution. Some of the agents, underwriters or dealers, or their affiliates, may engage in transactions with or perform services for us and our subsidiaries in the ordinary course of their business.

LEGAL MATTERS

Gibson, Dunn & Crutcher LLP and Hunton & Williams LLP, Richmond, Virginia, have each rendered an opinion with respect to the validity of the securities that may be offered under this prospectus. We filed these opinions as exhibits to the registration statement of which this prospectus is a part. If counsel for any underwriters passes on legal matters in connection with an offering made under this prospectus, we will name that counsel in the prospectus supplement relating to that offering.

EXPERTS

The consolidated financial statements of Atmos Energy appearing in Atmos Energy Corporation’s Annual Report (Form 10-K) for the fiscal year ended September 30, 2012 (including the schedule appearing therein), and the effectiveness of Atmos Energy Corporation’s internal control over financial reporting as of September 30, 2012 have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

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With respect to the unaudited condensed consolidated interim financial information of Atmos Energy for the three-month periods ended December 31, 2012 and 2011, incorporated herein by reference, Ernst & Young LLP reported that they have applied limited procedures in accordance with professional standards for a review of such information. However, their separate report dated February 7, 2013, included in our quarterly report on Form 10-Q for the three-month period ended December 31, 2012, and incorporated herein by reference, states that they did not audit and they do not express an opinion on that interim financial information. Accordingly, the degree of reliance on their report on such information should be restricted in light of the limited nature of the review procedures applied. Ernst & Young LLP is not subject to the liability provisions of Section 11 of the Securities Act of 1933, as amended, for their report on the unaudited interim financial information because that report is not a “report” or a “part” of the Registration Statement prepared or certified by Ernst & Young LLP within the meaning of Sections 7 and 11 of the Securities Act of 1933.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). You may read and copy this information at the Public Reference Room of the SEC, 100 F Street, N.E., Washington, D.C. 20549, at prescribed rates. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330.

The SEC also maintains an internet website that contains reports, proxy statements and other information about issuers, like us, who file electronically with the SEC. The address of that site is www.sec.gov. Unless specifically listed below under “Incorporation of Certain Documents by Reference” the information contained on the SEC website is not incorporated by reference into this prospectus.

You can also inspect reports, proxy statements and other information about us at the offices of the New York Stock Exchange, Inc., 20 Broad Street, New York, New York 10005.

We have filed with the SEC a registration statement on Form S-3, of which this prospectus is a part, that registers the securities we are offering. The registration statement, including the attached exhibits and schedules, contains additional relevant information about us and the securities offered. The rules and regulations of the SEC allow us to omit certain information included in the registration statement from this prospectus.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” information in this prospectus that we have filed with it. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus, except for any information that is superseded by information that is included directly in this prospectus or the applicable prospectus supplement relating to an offering of our securities.

We incorporate by reference into this prospectus the documents listed below and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the termination of our offering of securities. These additional documents include periodic reports, such as annual reports on Form 10-K and quarterly reports on Form 10-Q, and current reports on Form 8-K (other than information furnished under Items 2.02 and 7.01, which is deemed not to be incorporated by reference in this prospectus), as well as proxy statements (other than information identified in them as not incorporated by reference). You should review these filings as they may disclose a change in our business, prospects, financial condition or other affairs after the date of this prospectus.

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This prospectus incorporates by reference the documents listed below that we have filed with the SEC but have not been included or delivered with this document:

• Our annual report on Form 10-K for the year ended September 30, 2012;

• Our quarterly report on Form 10-Q for the three-month period ended December 31, 2012;

• Our current reports on Form 8-K filed with the SEC on October 2, 2012, December 7, 2012, December 11, 2012, December 12, 2012 (8-K/A), January 3, 2013, January 11, 2013, January 15, 2013, January 29, 2013 and February 15, 2013.

• The following pages and captioned text contained in our definitive proxy statement for the annual meeting of shareholders on February 13, 2013 and incorporated into our annual report on Form 10-K: pages 3 through 6 under the captions, “Corporate Governance and Other Board Matters — Independence of Directors” and “ — Related Person Transactions,” pages 9 and 10 under the captions, “Corporate Governance and Other Board Matters — Committees of the Board of Directors” and “— Other Board and Board Committee Matters — Human Resources Committee Interlocks and Insider Participation,” pages 10 and 11 under the captions, “Corporate Governance and Other Board Matters — Independence of Audit Committee Members, Financial Literacy and Audit Committee Financial Experts” and — “ Audit Committee Pre-Approval Policy,” pages 15 through 21 under the captions “Proposal One — Election of Directors — Nominees for Director” and “— Retiring Director,” pages 21 to 25 under the caption, “Director Compensation,” pages 25 to 27 under the caption, “Beneficial Ownership of Common Stock,” page 27 under the caption, “Human Resources Committee Report,” pages 27 through 40 under the caption, “Compensation Discussion and Analysis,” and pages 40 through 60 under the caption, “Named Executive Officer Compensation” through to the end of the caption “Proposal Three-Ratification of Appointment of Independent Registered Public Accounting Firm.”

These documents contain important information about us and our financial condition.

You may obtain a copy of any of these filings, or any of our future filings, from us without charge by requesting it in writing or by telephone at the following address or telephone number:

Atmos Energy Corporation

1800 Three Lincoln Centre

5430 LBJ Freeway

Dallas, Texas 75240

Attention: Susan Giles

(972) 934-9227

Our internet website address is www.atmosenergy.com. Information on or connected to our internet website is not part of this prospectus.

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$1,750,000,000

ATMOS ENERGY CORPORATION

Debt Securities

and

Common Stock

PROSPECTUS

March 28, 2013

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

Securities and Exchange Commission registration fee	$	*
Blue Sky fees, including counsel fees		**
Printing expenses		**
Trustee’s fees and expenses		**
Rating agency fees		**
State filing fees		**
Accounting fees and expenses		**
Legal fees and expenses		**
Miscellaneous expenses		**
Total	$	**

* Deferred in accordance with Rules 456(b) and 457(r) under the Securities Act of 1933.

** These fees and expenses are calculated based on the securities offered and the number of issuances and accordingly cannot be estimated at this time.

Item 15. Indemnification of Directors and Officers.

The Texas Business Organizations Code and the Virginia Stock Corporation Act permit, and in some cases require, corporations to indemnify directors and officers who are or have been a party or are threatened to be made a party to litigation against judgments, penalties, including excise and similar taxes, fines, settlements, and reasonable expenses under certain circumstances. Article IX of our Articles of Incorporation and Article IX of our Bylaws provide for indemnification of judgments, penalties, including excise and similar taxes, fines, settlements, and reasonable expenses, including attorney’s fees, and the advance payment or reimbursement of such reasonable expenses to directors and officers to the fullest extent permitted by law.

As authorized by Section 8.101 of the Texas Business Organizations Code, and Section 13.1-697 of the Virginia Stock Corporation Act, each of our directors and officers may be indemnified by us against expenses, including attorney’s fees, judgments, fines and amounts paid in settlement, actually and reasonably incurred in connection with the defense or settlement of any threatened, pending or completed legal proceedings in which he is involved by reason of the fact that he is or was a director or officer of ours if he acted in good faith and in a manner that he reasonably believed to be in or not opposed to our best interests, and, with respect to any criminal action or proceeding, if he had no reasonable cause to believe that his conduct was unlawful. In each case, such indemnity shall be to the fullest extent authorized by the Texas Business Organizations Code and the Virginia Stock Corporation Act. If the director or officer is found liable to us, or received an improper personal benefit from us, whether or not involving action in his official capacity, then indemnification will be limited to reasonable expenses actually incurred.

Article X of our Articles of Incorporation provides that no director shall be personally liable to us or our shareholders for monetary damages for any breach of fiduciary duty as a director except for liability:

• for any breach of duty of loyalty to us or our shareholders,

• for an act or omission not in good faith or which involves intentional misconduct or a knowing violation of law,

• for a transaction from which the director received an improper benefit, whether or not the benefit resulted from an action taken within the scope of the director’s office,

• for an act or omission for which the liability of a director is expressly provided by statute, or

• for an act related to an unlawful stock repurchase or payment of a dividend.

In addition, Article IX of our Articles of Incorporation and Article IX of our Bylaws require us to indemnify to the fullest extent authorized by law any person made or threatened to be made party to any action, suit or proceeding, whether criminal, civil, administrative, arbitrative or investigative, by reason of the fact that such person is or was a director or officer or, while a director or officer, serves or served at our request as a director, officer, partner, venturer, proprietor, trustee, employee, agent or similar functionary of any other enterprise.

We maintain an officers’ and directors’ liability insurance policy insuring officers and directors against certain liabilities, including liabilities under the Securities Act of 1933. The effect of such policy is to indemnify such officers and directors against losses incurred by them while acting in such capacities.

Item 16. Exhibits.

See the Exhibit Index attached to this registration statement and incorporated herein by reference.

Item 17. Undertakings.

(a) The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement; Provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

Provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

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(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(ii) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii) or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

The undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

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(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions described in Item 15, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

(d) The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under Section 305(b)(2) of the Trust Indenture Act.

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Signatures and Powers of Attorney

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Dallas, State of Texas, on March 28, 2013.

ATMOS ENERGY CORPORATION
By:	/s/ BRET J. ECKERT
	Bret J. Eckert
	Senior Vice President and
	Chief Financial Officer

KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Kim R. Cocklin and Bret J. Eckert, or either of them acting alone or together, with full power of substitution and resubstitution, as his or her true and lawful attorney-in-fact and agent, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments to this registration statement, including post-effective amendments (and any additional registration statement related thereto permitted by or under the Securities Act of 1933 and any and all amendments, thereto, including post-effective amendments) and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorney-in-fact and agent, or his substitute or resubstitute, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorney-in-fact and agent may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/S/ ROBERT W. BEST Robert W. Best	Executive Chairman of the Board	March 28, 2013
/S/ KIM R. COCKLIN Kim R. Cocklin	President and Chief Executive Officer (Principal Executive Officer) and Director	March 28, 2013
/S/ BRET J. ECKERT Bret J. Eckert	Senior Vice President and Chief Financial Officer (Principal Financial Officer)	March 28, 2013
/S/ CHRISTOPHER T. FORSYTHE Christopher T. Forsythe	Vice President and Controller (Principal Accounting Officer)	March 28, 2013
/S/ RICHARD W. DOUGLAS Richard W. Douglas	Director	March 28, 2013
/S/ RUBEN E. ESQUIVEL Ruben E. Esquivel	Director	March 28, 2013

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Signature	Title	Date
/S/ RICHARD K. GORDON Richard K. Gordon	Director	March 28, 2013
/S/ ROBERT C. GRABLE Robert C. Grable	Director	March 28, 2013
/S/ THOMAS C. MEREDITH Thomas C. Meredith	Director	March 28, 2013
/S/ NANCY K. QUINN Nancy K. Quinn	Director	March 28, 2013
/S/ RICHARD A. SAMPSON Richard A. Sampson	Director	March 28, 2013
/S/ STEPHEN R. SPRINGER Stephen R. Springer	Director	March 28, 2013
/S/ RICHARD WARE II Richard Ware II	Director	March 28, 2013

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EXHIBIT INDEX

Exhibit Number	Description	Incorporation by Reference from
1**	Underwriting Agreement
4.1	Restated Articles of Incorporation of Atmos Energy Corporation — Texas	Exhibit 3.1 to Form 10-Q dated March 31, 2010 (File No. 1-10042)
4.2	Restated Articles of Incorporation of Atmos Energy Corporation — Virginia	Exhibit 3.2 to Form 10-Q dated March 31, 2010 (File No. 1-10042)
4.3	Amended and Restated Bylaws of Atmos Energy Corporation (as of February 3, 2010)	Exhibit 3.2 to Form 8-K filed February 9, 2010 (File No. 1-10042)
4.4	Specimen Common Stock Certificate (Atmos Energy Corporation)	Exhibit 4.1 to Form 10-K for the fiscal year ended September 30, 2012 (File No. 1-10042)
4.5	Indenture dated as of March 26, 2009 between Atmos Energy Corporation and U.S. Bank National Association, Trustee	Exhibit 4.1 to Form 8-K filed March 26, 2009 (File No. 1-10042)
4.6**	Form of Supplemental Indenture or Officers’ Certificate
4.7**	Form of Global Debt Security
5.1*	Opinion of Gibson, Dunn & Crutcher LLP as to the validity of the securities being registered
5.2*	Opinion of Hunton & Williams LLP, Richmond, Virginia, as to the validity of the securities being registered
12	Computation of ratio of earnings to fixed charges	Exhibit 12 to Form 10-K for the fiscal year ended September 30, 2012 (File No. 1-10042) and Exhibit 12 to Form 10-Q for the three-month period ended December 31, 2012 (File No. 1-10042)
15*	Letter re Unaudited Interim Financial Information
23.1	Consent of Gibson, Dunn & Crutcher LLP	See Exhibit 5.1 of this Registration Statement
23.2	Consent of Hunton & Williams LLP, Richmond, Virginia	See Exhibit 5.2 of this Registration Statement
23.3*	Consent of Ernst & Young LLP
24	Power of Attorney	See signature pages of this Registration Statement
25*	Statement of eligibility of trustee for debt securities on Form T-1

* Filed herewith.

** To be filed by amendment hereto, pursuant to a Current Report on Form 8-K to be incorporated herein by reference or otherwise filed with the SEC.

EX-5.1

EXHIBIT 5.1

[LETTERHEAD OF GIBSON, DUNN & CRUTCHER LLP]

Client: 03896-00046

March 28, 2013

Atmos Energy Corporation

1800 Three Lincoln Centre

5430 LBJ Freeway

Dallas, Texas 75240

Re: Atmos Energy Corporation Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as counsel to Atmos Energy Corporation, a Texas and Virginia corporation (the “Company”), in connection with the preparation and filing with the Securities and Exchange Commission (the “Commission”) of a Registration Statement on Form S-3 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration under the Securities Act and the proposed issuance and sale from time to time pursuant to Rule 415 under the Securities Act, together or separately and in one or more series (if applicable) of:

(i) the Company’s unsecured debt securities, which may either be senior debt securities (“Senior Debt Securities”) or subordinated debt securities (“Subordinated Debt Securities” and, together with the Senior Debt Securities, the “Debt Securities”); and

(ii) shares of the Company’s common stock, no par value per share (the “Common Stock”).

The Debt Securities and Common Stock are collectively referred to herein as the “Securities.” The Debt Securities are to be issued under an indenture, dated March 26, 2009, entered into between the Company and U.S. Bank National Association, as indenture trustee (the “Base Indenture”).

In arriving at the opinions expressed below, we have examined originals, or copies certified or otherwise identified to our satisfaction as being true and complete copies of the originals, of the Base Indenture, forms of the Debt Securities, specimen Common Stock certificates and such other documents, corporate records, certificates of officers of the Company and of public officials and other instruments as we have deemed necessary or advisable to enable us to render these opinions. In our examination, we have assumed the genuineness of all signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals and the conformity to original documents of all documents submitted to us as copies. As to any facts material to these opinions, we have relied to the extent we deemed appropriate and without independent investigation upon statements and representations of officers and other representatives of the Company and others.

Atmos Energy Corporation

March 28, 2013

Page 2

We have assumed without independent investigation that:

(i) at the time any Securities are sold pursuant to the Registration Statement (the “Relevant Time”), the Registration Statement and any supplements and amendments thereto (including post-effective amendments) will be effective and will comply with all applicable laws;

(ii) at the Relevant Time, a prospectus supplement will have been prepared and filed with the Commission describing the Securities offered thereby and all related documentation and will comply with all applicable laws;

(iii) all Securities will be issued and sold in the manner stated in the Registration Statement and the applicable prospectus supplement;

(iv) at the Relevant Time, all corporate or other action required to be taken by the Company to duly authorize each proposed issuance of Securities and any related documentation (including (i) the due reservation of any shares of Common Stock for issuance upon conversion of any Debt Securities into Common Stock (a “Convertible Security”), and (ii) the execution (in the case of certificated Securities), delivery and performance of the Securities and any related documentation referred to in paragraphs 1 and 2 below) shall have been duly completed and shall remain in full force and effect;

(v) upon issuance of any Common Stock, including upon conversion of any Convertible Security, the total number of shares of Common Stock issued and outstanding will not exceed the total number of shares of Common Stock that the Company is then authorized to issue under its articles of incorporation and other relevant documents;

(vi) in the case of Debt Securities, at the Relevant Time, the Base Indenture shall have been duly qualified under the Trust Indenture Act of 1939, as amended;

(vii) at the Relevant Time, a definitive purchase, underwriting or similar agreement and any other necessary agreement with respect to any Securities offered or issued will have been duly authorized by all necessary corporate or other action of the Company and duly executed and delivered by the Company and the other parties thereto.

Atmos Energy Corporation

March 28, 2013

Page 3

Based on the foregoing and in reliance thereon, and subject to the assumptions, exceptions, qualifications and limitations set forth herein, we are of the opinion that:

1. With respect to any Debt Securities, when:

a. the terms and conditions of such Debt Securities have been duly established by supplemental indenture or officers’ certificate in accordance with the terms and conditions of the Base Indenture,

b. any such supplemental indenture or officers’ certificate has been duly executed and delivered by the Company and, if applicable, the trustee (together with the Base Indenture, the “Indenture”), and

c. such Debt Securities have been executed (in the case of certificated Debt Securities), delivered and authenticated in accordance with the terms of the applicable Indenture and issued and sold for the consideration set forth in the applicable definitive purchase, underwriting or similar agreement,

such Debt Securities will be legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms.

2. With respect to shares of Common Stock, when:

a. such shares of Common Stock have been duly executed (in the case of certificated shares) and delivered either (i) in accordance with the applicable definitive purchase, underwriting or similar agreement for the consideration provided for therein, or (ii) upon conversion of any Convertible Security, in accordance with the terms of such Convertible Security or the instrument governing such Convertible Security providing for such conversion, and for any additional consideration specified therein, and

b. any such Convertible Security is a legal, valid and binding obligation of the Company, enforceable against the Company in accordance with its terms,

such shares of Common Stock will be validly issued, fully paid and non-assessable.

The opinions expressed above are subject to the following exceptions, qualifications, limitations and assumptions:

A. We render no opinion herein as to matters involving the laws of any jurisdiction other than the State of New York and the United States of America and to the extent relevant for our opinions herein, the Texas Business Organizations Code. This opinion is limited to the effect of the current state of the laws of the State of New York and the United States of America, the Texas Business Organizations Code and the facts as they currently exist. We express no opinion regarding any federal or state laws or regulations related to the regulation of utilities. We assume no obligation to revise or supplement this opinion in the event of future changes in such laws or the interpretations thereof or such facts.

Atmos Energy Corporation

March 28, 2013

Page 4

B. We note that the Company is incorporated in the State of Texas and in the Commonwealth of Virginia and, to the extent that our opinions may be dependent upon such matters, we have assumed, without independent investigation, that the Company is a validly existing corporation in good standing under the laws of the Commonwealth of Virginia and that under the laws of the Commonwealth of Virginia: (i) the Company has all requisite power to execute, deliver and perform its obligations under the Indenture and the Debt Securities (collectively, the “Note Documents”), (ii) the authorization, execution, delivery and performance of the Note Documents by the Company and the performance of its obligations thereunder do not and will not violate the charter or bylaws of the Company or any law, regulation, order, judgment or decree applicable to the Company, (iii) the Note Documents will be duly executed and delivered by the Company and (iv) the Common Stock will be validly issued, fully paid and non-assessable. We understand that you are receiving an opinion of Virginia counsel as to matters relating to Virginia law.

C. The opinion above with respect to the Note Documents is subject to (i) the effect of any bankruptcy, insolvency, reorganization, moratorium, arrangement or similar laws affecting the rights and remedies of creditors’ generally, including without limitation the effect of statutory or other laws regarding fraudulent transfers or preferential transfers and (ii) general principles of equity, including without limitation concepts of materiality, reasonableness, good faith and fair dealing and the possible unavailability of specific performance, injunctive relief or other equitable remedies regardless of whether enforceability is considered in a proceeding in equity or at law.

D. We express no opinion regarding the effectiveness of (i) any waiver of stay, extension or usury laws or (ii) provisions relating to indemnification, exculpation or contribution, to the extent such provisions may be held unenforceable as contrary to public policy or federal or state securities laws.

You have informed us that you intend to issue Securities from time to time on a delayed or continuous basis, and we understand that prior to issuing any Securities pursuant to the Registration Statement (i) you will advise us in writing of the terms thereof, and (ii) you will afford us an opportunity to (x) review the operative documents pursuant to which such Securities are to be issued or sold (including the applicable offering documents), and (y) file such supplement or amendment to this opinion (if any) as we may reasonably consider necessary or appropriate.

We consent to the filing of this opinion as an exhibit to the Registration Statement, and we further consent to the use of our name under the caption “Legal Matters” in the Registration Statement and the prospectus that forms a part thereof. In giving these consents, we do not thereby admit that we are within the category of persons whose consent is required under

Atmos Energy Corporation

March 28, 2013

Page 5

Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

Very truly yours,

/s/ Gibson, Dunn & Crutcher LLP

EX-5.2

EXHIBIT 5.2

	HUNTON & WILLIAMS LLP RIVERFRONT PLAZA, EAST TOWER 951 EAST BYRD STREET RICHMOND, VIRGINIA 23219-4074 TEL 804 • 788 • 8200 FAX 804 • 788 • 8218
	FILE NO: 51645.000001

March 28, 2013

Atmos Energy Corporation

1800 Three Lincoln Centre

Dallas, Texas 75240

Atmos Energy Corporation

Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as special Virginia counsel for Atmos Energy Corporation, a Texas and Virginia corporation (the “Company”), for the purpose of providing this opinion in connection with the Company’s the Registration Statement on Form S-3 (the “Registration Statement”) to be filed with the Securities and Exchange Commission (the “SEC”) under the Securities Act of 1933 (as amended, the “Act”), on the date hereof, in connection with the offering and issuance from time to time by the Company of the following: (i) one or more series of its debt securities (the “Debt Securities”) and (ii) shares of its Common Stock, no par value per share (the “Common Stock” and together with the Debt Securities, the “Securities”). All capitalized terms which are not defined herein shall have the meanings assigned to them in the Registration Statement.

This opinion is being furnished in accordance with the requirements of Item 16 of Form S-3 and Item 601(b)(5)(i) of Regulation S-K promulgated under the Act.

In connection with this opinion, we have examined originals or copies, certified or otherwise identified to our satisfaction, of such corporate records of the Company, certificates of corporate officers of the Company and public officials and such other documents as we have deemed necessary for the purposes of rendering this opinion, including, among other things, (i) the Virginia Restated Articles of Incorporation (the “Articles of Incorporation”) and the Amended and Restated Bylaws (the “Bylaws”) of the Company, each as amended through the date hereof, (ii) a certificate issued by the State Corporation Commission of the Commonwealth of Virginia on March 20, 2013, to the effect that the Company is existing under the laws of the Commonwealth of Virginia and in good standing, (iii) resolutions of the Board of Directors of the Company, adopted at a meeting held on November 7, 2012, (iv) the Registration Statement, and (v) the indenture, dated as of March 26, 2009 (the “Indenture”), between the Company and U.S. Bank National Association, as trustee.

ATLANTA   AUSTIN   BANGKOK   BEIJING   BRUSSELS   CHARLOTTE   DALLAS   HOUSTON   LONDON   LOS ANGELES

McLEAN   MIAMI   NEW YORK   NORFOLK   RALEIGH   RICHMOND   SAN FRANCISCO   TOKYO   WASHINGTON

www.hunton.com

Atmos Energy Corporation

March 28, 2013

Page 2

For purposes of the opinions expressed below, we have assumed (i) the authenticity of all documents submitted to us as originals, (ii) the conformity to the originals of all documents submitted to us as certified, photostatic or electronic copies and the authenticity of the originals thereof, (iii) the legal capacity of natural persons, (iv) the genuineness of all signatures not witnessed by us and (v) the due authorization, execution and delivery of all documents by all parties and the validity, binding effect and enforceability thereof on such parties (other than the authorization, execution and delivery of documents by the Company).

As to factual matters, we have relied upon, and assumed the accuracy of, representations included in the documents submitted to us, upon certificates of officers of the Company and upon certificates of public officials. Except as otherwise expressly indicated, we have not undertaken any independent investigation of factual matters.

We do not purport to express an opinion on any laws other than those of the Commonwealth of Virginia.

The opinions set forth herein are subject to the following assumptions, qualifications and limitations being true and correct at or prior to the time of the delivery of any Security:

(a) the Board of Directors of the Company will have duly authorized and taken any necessary corporate action to approve the issuance and sale of shares of Common Stock in conformity with the Articles of Incorporation and Bylaws, each as amended through such time (subject to the further assumption that such instruments have not been amended from the date hereof in a manner that would affect any of the opinions rendered herein), and such authorization shall remain in effect and unchanged at all times during which such shares of Common Stock are offered and will not have been modified or rescinded (subject to the further assumption that the sale of any shares of Common Stock takes place in accordance with such authorization);

(b) the Registration Statement, and any amendments thereto (including post-effective amendments), filed under the Act and the effectiveness thereof will not have been terminated or rescinded;

(c) a prospectus supplement (a “Prospectus Supplement”) will have been prepared and filed with the SEC describing the shares of Common Stock offered thereby; and

Atmos Energy Corporation

March 28, 2013

Page 3

(d) all shares of Common Stock will be issued and sold in compliance with applicable federal and state securities laws and solely in the manner stated in the Registration Statement and the appropriate Prospectus Supplement and there will not have occurred any change in law affecting any of the opinions rendered herein.

Based upon the foregoing and such other information and documents as we have considered necessary for the purposes hereof, and subject to the assumptions, qualifications and limitations stated herein, we are of the opinion that:

1. The Company is validly existing as a corporation in good standing under the laws of the Commonwealth of Virginia.

2. The Company has the requisite corporate power to file the Registration Statement and to execute, deliver and perform its obligations under the Indenture and the Debt Securities (collectively, the “Note Documents”).

3. The authorization, execution and delivery of the Note Documents by the Company and the performance of its obligations under the Note Documents do not violate the Articles of Incorporation, the Bylaws or any law or regulation of the Commonwealth of Virginia or any order, judgment or decree of any court, regulatory body, administrative agency or governmental body of the Commonwealth of Virginia applicable to the Company.

4. When the Common Stock shall have been authorized, issued and sold within the limits and as described in the Registration Statement, and if in an underwritten offering, in accordance with the terms and conditions of the applicable underwriting agreement, and in a manner contemplated in the Registration Statement, including the Prospectus Supplement relating to the applicable offering of such Common Stock, the Common Stock will be validly issued and the Common Stock will be fully paid and nonassessable.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement, and we further consent to the use of our name under the caption “Legal Matters” in the Registration Statement and the prospectus that forms a part thereof. In giving these consents, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the SEC.

Atmos Energy Corporation

March 28, 2013

Page 4

This opinion is rendered as of the date hereof, and we disclaim any obligation to advise you of facts, circumstances, events or developments that hereafter may be brought to our attention and that may alter, affect or modify the opinion expressed herein. Our opinion is expressly limited to the matters set forth above and we render no opinion, whether by implication or otherwise, as to any other matters relating to the Company or the Securities.

Very truly yours,

/s/ Hunton & Williams LLP

EX-15

EXHIBIT 15

The Board of Directors and Shareholders of

Atmos Energy Corporation

We are aware of the incorporation by reference in the Registration Statement (Form S-3) of Atmos Energy Corporation for the registration of $1,750,000,000 of debt securities and common stock to be filed with the Securities and Exchange Commission of our reports dated February 7, 2013, relating to the unaudited condensed consolidated interim financial statements of Atmos Energy Corporation that are included in its Form 10-Q for the quarter ended December 31, 2012.

/s/ ERNST & YOUNG LLP

Dallas, Texas

March 25, 2013

EX-23.3

EXHIBIT 23.3

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption “Experts” in the Registration Statement on Form S-3 and related Prospectus of Atmos Energy Corporation for the registration of $1,750,000,000 of its debt securities or common stock and to the incorporation by reference therein of our report dated November 12, 2012, with respect to the consolidated financial statements and schedule of Atmos Energy Corporation, and the effectiveness over financial reporting of Atmos Energy Corporation, included in its Annual Report on Form 10-K for the year ended September 30, 2012, filed with the Securities and Exchange Commission.

/s/ ERNST & YOUNG LLP

Dallas, Texas

March 25, 2013

EX-25

EXHIBIT 25

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM T-1

STATEMENT OF ELIGIBILITY UNDER

THE TRUST INDENTURE ACT OF 1939 OF A

CORPORATION DESIGNATED TO ACT AS TRUSTEE

¨ Check if an Application to Determine Eligibility of a Trustee Pursuant to Section 305(b)(2)

U.S. BANK NATIONAL ASSOCIATION

(Exact name of Trustee as specified in its charter)

31-0841368

I.R.S. Employer Identification No.

800 Nicollet Mall Minneapolis, Minnesota	55402
(Address of principal executive offices)	(Zip Code)

Jack Ellerin

U.S. Bank National Association

1349 West Peachtree Street

Suite 1050

Atlanta, GA 30309

(404) 898-8830

(Name, address and telephone number of agent for service)

ATMOS ENERGY CORPORATION

(Issuer with respect to the Securities)

Texas and Virginia	75-1743247
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

1800 Three Lincoln Centre 5430 LBJ Freeway Dallas, Texas	75240
(Address of Principal Executive Offices)	(Zip Code)

Debt Securities

(Title of the Indenture Securities)

FORM T-1

Item 1. GENERAL INFORMATION. Furnish the following information as to the Trustee.

a) Name and address of each examining or supervising authority to which it is subject.

Comptroller of the Currency

Washington, D.C.

b) Whether it is authorized to exercise corporate trust powers.

Yes

Item 2. AFFILIATIONS WITH OBLIGOR. If the obligor is an affiliate of the Trustee, describe each such affiliation.

None

Items 3-15 Items 3-15 are not applicable because to the best of the Trustee’s knowledge, the obligor is not in default under any Indenture for which the Trustee acts as Trustee.

Item 16. LIST OF EXHIBITS: List below all exhibits filed as a part of this statement of eligibility and qualification.

1. A copy of the Articles of Association of the Trustee.*

2. A copy of the certificate of authority of the Trustee to commence business, attached as Exhibit 2.

3. A copy of the certificate of authority of the Trustee to exercise corporate trust powers, attached as Exhibit 3.

4. A copy of the existing bylaws of the Trustee.**

5. A copy of each Indenture referred to in Item 4. Not applicable.

6. The consent of the Trustee required by Section 321(b) of the Trust Indenture Act of 1939, attached as Exhibit 6.

7. Report of Condition of the Trustee as of December 31, 2012 published pursuant to law or the requirements of its supervising or examining authority, attached as Exhibit 7.

* Incorporated by reference to Exhibit 25.1 to Amendment No. 2 to registration statement on S-4, Registration Number 333-128217 filed on November 15, 2005.

** Incorporated by reference to Exhibit 25.1 to registration statement on S-4, Registration Number 333-166527 filed on May 5, 2010.

2

SIGNATURE

Pursuant to the requirements of the Trust Indenture Act of 1939, as amended, the Trustee, U.S. BANK NATIONAL ASSOCIATION, a national banking association organized and existing under the laws of the United States of America, has duly caused this statement of eligibility and qualification to be signed on its behalf by the undersigned, thereunto duly authorized, all in the City of Atlanta, State of Georgia on the 26^th of March, 2013.

By:	/s/ Jack Ellerin
	Jack Ellerin
	Vice President

3

Exhibit 2

Comptroller of the Currency

Administrator of National Banks

Washington, DC 20219

CERTIFICATE OF CORPORATE EXISTENBCE

I, Thomas J. Curry, Comptroller of the Currency, do hereby certify that:

1. The Comptroller of the Currency, pursuant to Revised Statutes 324, et seq, as amended, and 12 USC 1, et, seq, as amended, has possession, custody, and control of all records pertaining to the chartering, regulation, and supervision of all national banking associations.

2. “U.S. Bank National Association,” Cincinnati, Ohio (Charter No. 24), is a national banking association formed under the laws of the United States and is authorized there under to transact the business of banking on the date of this certificate.

IN TESTIMONY WHEREOF, today,

November 28, 2012, I have hereunto

Subscribed my name and caused my seal of

Office to be affixed to these presents at the

U.S. Department of the Treasury, in the City

of Washington, District of Columbia.

Comptroller of the Currency

4

Exhibit 3

Comptroller of the Currency

Administrator of National Banks

Washington, DC 20219

CERTIFICATE OF CORPORATE EXISTENBCE AND FIDLCIARY POWERS

I, Jone Walst Comptroller of the Currency, do hereby certify that:

1. The Comptroller of the Currency, pursuant to Revised Statutes 324, et seq, as amended, and 12 USC 1, et, seq, as amended, has possession, custody, and control of all records pertaining to the chartering, regulation, and supervision of all national banking associations.

2. “U.S. Bank National Association,” Cincinnati, Ohio (Charter No. 24), is a national banking association formed under the laws of the United States and is authorized there under to transact the business of banking on the date of this certificate.

IN TESTIMONY WHEREOF, today,

March 19, 2012, I have hereunto

Subscribed my name and caused my seal of

Office to be affixed to these presents at the

U.S. Department of the Treasury, in the City

of Washington, District of Columbia.

Acting Comptroller of the Currency

5

Exhibit 6

CONSENT

In accordance with Section 321(b) of the Trust Indenture Act of 1939, the undersigned, U.S. BANK NATIONAL ASSOCIATION hereby consents that reports of examination of the undersigned by Federal, State, Territorial or District authorities may be furnished by such authorities to the Securities and Exchange Commission upon its request therefor.

Dated: March 26, 2013

By:	/s/ Jack Ellerin
	Jack Ellerin
	Vice President

6

Exhibit 7

U.S. Bank National Association

Statement of Financial Condition

As of 12/31/2012

($000’s)

	12/31/2012
Assets
Cash and Balances Due From Depository Institutions	$	8,252,302
Securities		74,022,528
Federal Funds		74,234
Loans & Lease Financing Receivables		219,884,343
Fixed Assets		5,024,268
Intangible Assets		12,542,566
Other Assets		25,288,375
Total Assets	$	345,088,616
Liabilities
Deposits	$	253,686,214
Fed Funds		4,291,213
Treasury Demand Notes		0
Trading Liabilities		404,237
Other Borrowed Money		30,911,125
Acceptances		0
Subordinated Notes and Debentures		4,736,320
Other Liabilities		11,473,186
Total Liabilities	$	305,502,295
Equity
Common and Preferred Stock		18,200
Surplus		14,133,290
Undivided Profits		23,981,892
Minority Interest in Subsidiaries	$	1,452,939
Total Equity Capital	$	39,586,321
Total Liabilities and Equity Capital	$	345,088,616

7