S-8

Registration No. 33-          

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

_____________________

FORM S-8

REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

KEITHLEY INSTRUMENTS, INC.

(Exact name of registrant as specified in its charter)

Ohio	34-0794417
(State of incorporation or organization)	(IRS Employer Identification No.)
28775 Aurora Road, Solon, Ohio	44139
(Address of principal executive offices)	(Zip Code)

Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan

(Full Title of the Plan)

Joseph P. Keithley, Chairman, President and Chief Executive Officer
Keithley Instruments, Inc.
28775 Aurora Road, Solon, Ohio 44139
(Name and address of agent for service)

(440) 248-0400
(Telephone number, including area code, of agent for service)

CALCULATION OF REGISTRATION FEE

		Proposed Maximum		Proposed Maximum
Title of Securities	Amount to be	Offering Price Per		Aggregate Offering		Amount of
to be Registered (1)	Registered (2)	Share (3)		Price (3)		Registration Fee
Common Shares, without par value	500,000 shares	$	11.84	$	5,920,000	$	633.44

1. In addition, pursuant to Rule 416(c) under the Securities Act of 1933, the Registration Statement also covers an indeterminate number of interests to be offered or sold pursuant to the employee benefit plans described herein.

2. This Registration Statement shall also cover any additional Common Shares which become issuable under the Plan being registered pursuant to this Registration Statement by reason of any stock dividend, stock split, recapitalization or any other similar transaction effected without the receipt of considerations which results in an increase in the number of the outstanding Common Share of Keithley Instruments, Inc.

3. Estimated in accordance with Rule 457 solely for the purpose of determining the registration fee, based on the average of the high and low reported sale prices on June 14, 2006, of the Registrant’s Common Shares as reported on the New York Stock Exchange.

PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

     The SEC allows us to “incorporate by reference” the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act:

a)	Our Annual Report on Form 10-K for the fiscal year ended September 30, 2005;
b)	All other reports filed by the Company pursuant to Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, since September 30, 2005;
c)	The description of the Company’s Common Shares contained in Item 11 of the Registrant’s Form 10 Registration Statement (No. 0-13648) as declared effective on July 31, 1985, relating to the registration of the Registrant’s Common Shares under Section 12(g) of the Exchange Act; and
d)	All documents subsequently filed by us pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a post-effective amendment which indicates that all of the Common Shares offered pursuant to this Registration Statement have been sold or which deregisters all Common Shares then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of filing of such documents.

     Any statement contained in a document incorporated by reference herein as set forth above shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document incorporated by reference herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

     You may request a copy of these filings at no cost by writing to the following address: Keithley Instruments, Inc., 28775 Aurora Road, Solon, Ohio 44139, or by calling us at 440-248-0400.

Item 4. Description of Securities.

     Not applicable.

Item 5. Interests of Named Experts and Counsel.

     Not applicable.

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Item 6. Indemnification of Directors and Officers.

     Section 1701.13(E) of the Ohio Revised Code permits a corporation to indemnify or agree to indemnify officers and directors against certain liabilities. Pursuant to Section 1701.13(E) and subject to certain limitations contained therein, Article V of the Company’s Code of Regulations provides that the Company will indemnify any director or officer or any former director or officer of the Company against expenses, including attorney’s fees, judgments, fines and amounts paid in settlement, actually and reasonably incurred by him or her by reason of the fact that he or she is or was such director or officer of the Company or is or was serving at the request of the Company as a director, trustee, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise in connection with any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative.

Item 7. Exemption from Registration Claimed.

     Not applicable.

Item 8. Exhibits.

Number	Description
4.1	Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan, as amended.
5.1	Opinion of Baker & Hostetler LLP as to legality of the Common Shares being registered
23.1	Consent of PricewaterhouseCoopers LLP
23.2	Consent of Baker & Hostetler (included in Opinion filed as Exhibit 5.1 hereto)
24.1	Power of Attorney (included on the signature page hereto)

Item 9. 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

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	Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective Registration Statement.
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) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in 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.
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.

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 Exchange Act that is incorporated by reference in this Registration Statement shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

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, 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.

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SIGNATURES

     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-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Solon, State of Ohio, on this 15 day of June, 2006.

KEITHLEY INSTRUMENTS, INC. (Registrant)
By	/s/ Joseph P. Keithley
	Joseph P. Keithley Chairman, President and Chief Executive Officer

POWER OF ATTORNEY

     KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints, Joseph P. Keithley and Mark J. Plush, or either of them, his true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him and in his name, place, and stead, in any and all capacities, to sign any and all pre- or post-effective amendments to this Registration Statement, and to file the same with all exhibits hereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or his substitutes may lawfully do or cause to be done by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this Registrant Statement has been signed by the following persons in the capacities indicated on the 15 day of June, 2006.

Signature	Title
/s/ Joseph P. Keithley Joseph P. Keithley	Chairman of the Board of Directors, President and Chief Executive Officer (Principal Executive Officer)
/s/ Mark J. Plush Mark J. Plush	Vice President and Chief Financial Officer (Principal Financial and Accounting Officer)
/s/ Brian R. Bachman Brian R. Bachman	Director
/s/ James T. Bartlett James T. Bartlett	Director

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Signature	Title
/s/ James B. Griswold James B. Griswold	Director
/s/ Leon J. Hendrix, Jr. Leon J. Hendrix, Jr.	Director
/s/ Brian J. Jackman Brian J. Jackman	Director
/s/ N. Mohan Reddy N. Mohan Reddy	Director
/s/ Thomas A. Saponas Thomas A. Saponas	Director
/s/ Barbara V. Scherer Barbara V. Scherer	Director
/s/ R. Elton White R. Elton White	Director

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EXHIBIT INDEX

Exhibit
Number	Description
4.1	Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan, as amended
5.1	Opinion of Baker & Hostetler as to legality of the Common Shares being registered
23.1	Consent of PricewaterhouseCoopers LLP
23.2	Consent of Baker & Hostetler (included in Exhibit 5.1)
24.1	Power of Attorney (contained on the signature page hereof).

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EX-4.1

Exhibit 4.1

Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan
(As Amended on February 11, 2006)

This is a conformed copy of the Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan as adopted by the Board of Directors on December 5, 2005 (the “Plan”) which incorporates the changes to the Plan made by an amendment to the Keithley Instruments, Inc. 2005 Employee Stock Purchase and Dividend Reinvestment Plan approved on February 11, 2006 by the Board of Directors

KEITHLEY INSTRUMENTS, INC.
2005 EMPLOYEE STOCK PURCHASE AND DIVIDEND REINVESTMENT PLAN

Section I — Purpose

     This 2005 Employee Stock Purchase and Dividend Reinvestment Plan (the “Plan”) is adopted and established by Keithley Instruments, Inc., an Ohio corporation (the “Company”), effective as of June 1, 2005, subject only to appropriate approval by its shareholders, for the general benefit of the employees of the Company and certain of the Company’s subsidiary corporations. The purpose of the Plan is to facilitate the purchase by eligible employees of common shares, without par value, of Keithley Instruments, Inc. (“Stock”). The Plan is intended to meet the requirements of Section 423 of the Internal Revenue Code of 1986, as amended (the “Code”).

Section II — Agent

     National City Bank, Cleveland, Ohio, is hereby appointed to act as agent of the Company and of the participants under this Plan (the “Agent”).

Section III — Eligible Employees

     (a) In General. All employees of the Company, and all employees of those subsidiary corporations (as defined in Section 424 of the Code) identified and listed in Attachment A hereto (as modified by the Chief Financial Officer of the Company, no more frequently than annually), are eligible to participate in the Plan, other than temporary employees of the Company or any such subsidiary corporation who (i) customarily are employed for less than five (5) months in any calendar year, or (ii) customarily work twenty (20) hours or less per week. All individuals who satisfy the requirements set forth in the preceding sentence (individually, an “Eligible Employee,” and collectively, “Eligible Employees”) shall be granted rights to purchase Stock hereunder, so long as they continue to satisfy such requirements, and shall have the same rights and privileges as every other such Eligible Employee.

     (b) Limitations on Rights. An Eligible Employee shall not be entitled to purchase Stock under the Plan if (i) such purchase would cause such Eligible Employee to own Stock (including any shares of Stock which would be owned if such Eligible Employee purchased all of the Stock made available for purchase by such Eligible Employee under all options or rights then held by such Eligible Employee, whether or not then exercisable) representing five percent (5%) or more of the total combined voting power or value of all classes of stock of the Company or any subsidiary corporation; or (ii) such purchase would cause such Eligible Employee to have rights to purchase more than $25,000 of Stock under the Plan (and under all other stock purchase plans of the Company and its subsidiary corporations which satisfy the requirements of Section 423 of the Code) for any calendar year in which such rights are outstanding (based on the fair market value of such Stock, determined as of the commencement date of the Subscription Period and otherwise in accordance with Section IV(b) hereof). For purposes of clause (i) of this subparagraph (b), the attribution rules set forth in Section 424(d) of the Code and related regulations shall apply. For purposes of applying the $25,000 limitation of clause (ii) of this subparagraph (b), the number of shares of Stock eligible for purchase in one Plan Year may not be carried

over to any other Plan Year; provided, that the $25,000 limitation will be determined on a calendar year basis and not a Plan Year basis. In applying the limitation of clause (ii) of this subparagraph (b), in the event an option to purchase shares of Stock is outstanding in more than one calendar year because the Subscription Period extends across two calendar years, an Eligible Employee shall have the right to purchase up to $50,000 of Stock under the Plan for such Subscription Period, but applying such limit first to the first calendar year in which such option is outstanding and after taking into account all other stock purchased for such Eligible Employee hereunder. In the event more than one Subscription Period is in affect with respect to an Eligible Employee during the course of a given calendar year, the $25,000 limitation of clause (ii) of this subparagraph (b) shall be applied first to that Subscription Period with the earliest commencement date.

Section IV — Enrollment and Subscription Periods

     (a) Enrolling in the Plan. To participate in the Plan, an Eligible Employee must enroll in the Plan. Enrollment for a given Plan Year, and for each Subscription Period commencing during such Plan Year, will take place during the “Enrollment Period,” which shall consist of no less than a thirty (30)-day period and no greater than a forty-five (45) day period and be held within the ninety (90-day period immediately preceding the commencement of the Subscription Period to which such Enrollment Period relates. The initial Enrollment Period shall commence June 1, 2005 and end June 30, 2005 (inclusive), and apply with respect to the rights granted under the Plan for the Plan Year commencing July 1, 2005 (or if later, the effective date of the registration statement to be filed in accordance with Section XIX(a) hereof).

     (b) The Subscription Period. Any employee who is an Eligible Employee and desires to subscribe to purchase Stock under the Plan must make and file with the Company a subscription agreement that complies with Section VIII hereof during the applicable Enrollment Period. Such agreement shall be effective for the subscription period immediately following such Enrollment Period. There shall be at least one subscription period (a “Subscription Period”) each and every 12 months during the term of this Plan. The duration of each Subscription Period shall be established by the Board of Directors of the Company (the “Board”), or by a standing committee of the Board as the Board’s delegee, but in any event acting in the Board’s (or such delegee’s) discretion. If not otherwise established by the Board, the Subscription Period for a Plan Year shall commence on the first day of July and ending on the following June 30^th.

     (c) Changing Enrollment. The offering of Stock under the Plan shall occur only during a Subscription Period, and shall be made only to those Eligible Employees properly enrolled for that Subscription Period. Once enrolled, the Company will inform the Agent of such fact and those Eligible Employees so enrolled will thereupon become “Participants” under the Plan. Once enrolled, a Participant shall continue to be eligible to participate in the Plan for each succeeding Subscription Period until he or she terminates his or her participation or ceases to be an Eligible Employee. If a Participant desires to change his or her rate of contribution, he or she may do so effective for the next Subscription Period by filing a new authorization for payroll deduction and subscription agreement with the Company during the Enrollment Period immediately preceding such Subscription Period.

Section V — Term of Plan

     This Plan shall be in effect from the date of its adoption until it is terminated by action of the Board. The Plan shall be submitted to the shareholders of the Company for approval as soon as practical, but in any event not later than 12 months after the date of its adoption by the Board.

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Section VI — Number of Shares of Stock to be Made Available

     The total number of shares of Stock made available for purchase by Eligible Employees hereunder is Five Hundred Thousand (500,000), which may be authorized but unissued shares, treasury shares, or shares purchased for or on behalf of the Plan in the open market. When such shares of Stock are fully subscribed, the Plan shall either be continued through additional authorizations of shares made by the Board, or shall be terminated in accordance with Section XVII hereof.

Section VII — Subscription Price

     (a) Presumptive Subscription Price. Unless modified by the Board in accordance with Section VII(b), the “Subscription Price” for each share of Stock purchased for an Eligible Employee during a Subscription Period shall be 95% of the fair market value of the Stock, determined as of the commencement of such Subscription Period. The fair market value of the Stock will be determined in accordance with Section VII(c) hereof.

     (b) Modification of Subscription Price. The Board, in its discretion, may modify the Subscription Price set forth in Section VII(a) above by written action taken prior to the beginning of the Subscription Period for which such modification is to be effective. In the event the Board adopts a modified Subscription Price, such Subscription Price shall not be less than the lowest fair market value of a share of such Stock within the twelve (12) month period immediately preceding the first day of the applicable Subscription Period, and shall not be greater than the highest fair market value of a share of such Stock within the twelve month period immediately preceding the first day of the applicable Subscription Period. Notwithstanding the preceding sentence to the contrary, in no event will the Subscription Price of a share of Stock be the lesser of (i) 85% of the fair market value of a share of such Stock on the last trading day before the first day of each Subscription Period (which for Plan purposes shall be considered the date the right to purchase such Stock is granted to, and first exercisable by a Participant); or (ii) 85% of the fair market value of such share of such Stock on the last trading day of such Subscription Period (which for Plan purposes shall be considered the date each such right to purchase such Stock is actually exercised).

     (c) Determining The Price of Stock. For purposes of this Section, the fair market value of a share shall be the last reported sale price on the New York Stock Exchange or such other stock exchange on which a share of Stock is listed on the day in question (or if there is no reported sale on that day, on the most recent previous business day within a period of not more than five business days).

Section VIII — Amount of Contribution; Method of Payment

     (a) Payroll Withholding. Except as otherwise specifically provided herein, the Subscription Price will be payable by each Participant by means of payroll withholding. However, for any Participant not maintained on the Company’s payroll, such Participant shall be entitled to satisfy the Subscription Price by tendering to the Company (or its delegee) an amount, by money order or check drawn against an account with sufficient funds, that satisfies such Participant’s Subscription Price. The minimum withholding shall be equal to twenty dollars ($20.00) per month from a Participant’s Base Pay; the maximum withholding shall be an amount equal to one hundred percent (100%) of a Participant’s Base Pay (rounded to the nearest dollar), subject to any applicable tax or other withholding limitations. In any event, the total withholding permitted to be made by any Participant for a Subscription Period or Subscription Periods shall not exceed $25,000 for each calendar year as prescribed by Section 423(b)(8)

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of the Code. The actual percentage of Base Pay to be deducted shall be specified by a Participant in his or her authorization for payroll withholding.

     (b) Base Pay. For purposes of paragraph (a), above, “Base Pay” means the regular compensation which a Participant is entitled to receive on a pay day. Base Pay shall not include overtime, bonuses, or other items which are not considered to be regular earnings.

     (c) Application of Withholding Rules. Payroll withholding will commence with the first paycheck issued during the Subscription Period and will continue with each paycheck throughout the entire Subscription Period, except for pay periods for which a Participant receives no compensation (i.e., uncompensated personal leave, leave of absence, etc.). Any pay period which overlaps two Subscription Periods will be credited in its entirety to the Subscription Period in which it is paid. Payroll withholding shall be retained by the employer or other party responsible for making payment to the Participant, until applied to the purchase of shares as described in Section IX and the satisfaction of any related federal, state or local withholding obligations (including any employment tax obligations), or until returned to such Participant in connection with a withdrawal from the Plan or a revocation of authorization described in Section XIII. Any amounts held by an employer or other party in connection with or as a result of payroll withholding made pursuant to the Plan and pending the purchase of shares hereunder shall be considered non-interest bearing, unsecured indebtedness extended to such employer or other party by such Participant.

Section IX — Purchasing, Transferring Stock

     (a) Maintenance of Plan Account. The Company shall maintain a “Plan Account” in the name of each Participant. At the close of each pay period, the amount deducted and retained by the employer or other party from a Participant’s Base Pay will, for bookkeeping purposes only, be credited by the Company to such Participant’s Plan Account. As of the last day of each Subscription Period (unless a Participant has given written notice to the Company of his or her withdrawal or revocation of authorization), such Participant’s right to purchase Stock will be exercised automatically for him or her; upon such automatic exercise, the amount then credited to such Participant’s Plan Account for the purpose of purchasing shares will be divided by the Subscription Price for such Subscription Period (using the applicable discount determined pursuant to Section VII(a) hereof), and there shall be transferred to such Participant’s Plan Account by the Agent the number of shares of Stock which results. Participants shall not receive any interest on amounts held by an employer, the Company, or any other party (including the Agent) and credited to Plan Accounts established and maintained under this Plan.

     (b) Insufficient Number of Available Shares. In the event the number of shares of Stock subscribed for any Subscription Period exceeds the number of shares of Stock available for sale under the Plan for such Period, the number of shares of Stock actually available for sale hereunder shall be allocated by the Agent among the Participants in proportion to that portion of their Plan Account balances committed to the purchase of Stock for such Subscription Period.

     (c) Handling Excess Shares. In the event that the number of shares of Stock which would be credited to any Participant’s Plan Account in any Subscription Period exceeds the limit specified in Section III(b) hereof, such Participant’s Account shall be credited with the maximum number of shares permissible, and all remaining amounts will be refunded in cash.

     (d) Status Reports. As soon as practical following the close of each Subscription Period but in no event more than thirty (30) days following the close of such Subscription Period, the Agent shall report to each Participant the number of shares of Stock purchased on his or her behalf for such Subscription Period, and the total shares held on behalf of such Participant in his or her Plan

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Account. The Agent shall hold in its name or in the name of its nominee all shares so purchased and allocated. No certificate will be issued to a Participant for shares held in his or her Plan Account unless he or she so requests in writing, or unless such Participant’s active participation in the Plan is terminated due to death, separation from service or retirement.

     (e) In Service Stock Withdrawals. A Participant may request that a certificate for all or part of the full shares of Stock held in his or her Plan Account be sent to him or her after the relevant shares of Stock have been purchased and allocated. All such requests must be submitted in writing to the Agent. No certificate for a fractional share will be issued. The fair market value of any fractional shares, as determined pursuant to Section VII on the date of withdrawal of all shares credited to a Participant’s Plan Account, shall be paid in cash to such Participant. Any Participant requesting issuance of a Stock certificate prior to the date active participation ceases shall be solely responsible for paying and discharging all applicable fees and other associated with such issuance prior to the date any distribution of a certificate evidencing ownership of such shares occurs.

Section X — Dividends and Other Distributions

     (a) Reinvestment of Dividends. Cash dividends and other cash distributions received by the Agent on shares held in its custody hereunder will be credited to the Plan Accounts of individual Participants in accordance with their interests in the shares of Stock with respect to which such dividends or distributions are paid or made, less any applicable withholding, and will be applied, as soon as practical after the receipt thereof by the Agent, to the purchase in the open market at prevailing market prices (without any adjustment or discount otherwise provided for under Section VII hereof) of the number of whole shares of Stock capable of being purchased with such funds, after deduction of any bank service fees, brokerage charges and transfer taxes payable in connection with the purchase of such shares that are not otherwise paid by the Company.

     (b) Stock to Be Held in Agent’s Name. All purchases of shares of Stock made pursuant to this Section will be made in the name of the Agent or its nominee, shall be held as provided in Section IX hereof, and shall be transferred and credited (to the nearest one one-thousandth of a share) to the Plan Accounts of the individual Participant(s) to which such dividends or other distributions were credited. Dividends paid in the form of Stock will be allocated by the Agent, as and when received, with respect to shares held in its custody hereunder to the Plan Accounts of individual Participants (to the nearest one one-thousandth of a share) in accordance with such Participants’ interests in such shares with respect to which such dividends were paid. Property, other than shares of Stock or cash, received by the Agent as a distribution on shares held in its custody hereunder, shall be sold by the Agent for the accounts of those Participants to whom such property is attributable or allocable, and the Agent shall treat the proceeds of such sale in the same manner as cash dividends received by the Agent on shares held in its custody hereunder.

     (c) Tax Responsibilities. It is understood that the automatic reinvestment of dividends under the Plan will not relieve a Participant or other employee of any federal, state, local, or foreign income or other tax which may be due on or with respect to such dividends. The Agent shall report to each Participant the amount of dividends credited to his or her Plan Account.

     (d) Withholding on Payments Made to Non-Resident Aliens. The Agent shall be authorized and empowered to comply with any and all federal withholding laws relating to the payment of income items to non-resident aliens.

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Section XI — Voting of Stock

     Shares of Stock held for a Participant in his or her Plan Account will be voted in accordance with such Participant’s express written directions. In the absence of any such directions, such Stock will not be voted.

Section XII — Sale of Stock

     Subject to the provisions of Section XIX, a Participant may direct the Agent to sell all or part of the shares held on behalf of such Participant at any time, without having to first withdraw any shares of Stock from the Plan, by giving written notice to the Agent. Upon receipt of such a notice, the Agent shall, as soon as practical thereafter, sell such shares in the open market at the prevailing market price and transmit the net proceeds of such sale (less any bank service fees, brokerage charges and transfer taxes) to such Participant, but only so long as such Participant’s signature is guaranteed by a bank or trust company.

Section XIII — Withdrawals from the Plan

     (a) General Rule. By giving written notice to the Company, a Participant may at any time withdraw from the Plan or, without withdrawing from the Plan but by giving written notice to the Company, revoke his or her authorization for payroll deduction for the Subscription Period in which such revocation is made. In the event a Participant withdraws from the Plan or revokes such authorization, such Participant may withdraw the amount credited to such Participant’s Plan Account which has not previously been used to purchase shares of Stock.

     (b) Refund of Amounts Not Used to Purchase Shares. At the time of any withdrawal or revocation under this Section, the amount credited to a Participant’s Plan Account which has not previously been used to purchase shares of Stock will be refunded in cash.

     (c) Withdrawal of Shares. Upon any withdrawal under this Section, a Participant, in his or her notice of withdrawal election, may elect to receive either shares of Stock or cash for the full number of shares of Stock then being held in his or her Plan Account. If a Participant elects cash, the Agent shall sell such shares (whether in the open market, or otherwise) and send the net proceeds (less any bank service fees, brokerage charges and transfer taxes) to such Participant, but only if such Participant’s signature on such election has been guaranteed by a bank or trust company. If no election is made in a notice of withdrawal, a certificate shall be issued for all full shares of Stock held in such Participant’s Account. In every case of withdrawal from the Plan, fractional shares allocated to a Participant’s Plan Account will be paid in cash at the market value of such Stock on the date such withdrawal becomes effective, as determined pursuant to Section VII.

Section XIV — Separation from Employment

     Separation from employment for any reason, including death, disability, a termination of employment (regardless of the reason(s) therefore) shall be treated as a withdrawal from the Plan as described in Section XIII. For purposes of this Section XIV, an Eligible Employee will not be deemed to have terminated employment or failed to remain in the continuous employ of the Company, or to have ceased to qualify as an Eligible Employee, in the event such employee is absent from active employment due to sick leave, military leave of absence, a leave of absence required to be provided pursuant to the Family and medical Leave Act of 1993 or any other leave of absence approved by the Committee or

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required by applicable federal, state, or local law; provided, that such leave is for a period of not more than ninety (90) days or such Employee holds reemployment rights with the Company that are protected by state or federal statute. A service fee will not be charged for any withdrawal attributable to a separation from employment.

Section XV — Assignment

     No Eligible Employee, Participant, or other person, may assign, alienate, or otherwise transfer his or her right or rights to purchase Stock under this Plan to any other person or party; any attempt to so assign, alienate or transfer shall be void. A Participant’s right to purchase Stock under this Plan may be exercisable during such Participant’s lifetime only by that Participant.

Section XVI — Adjustment of and Changes in Stock

     In the event that the shares of Stock are changed or converted into, or exchanged for, a different number or kind of shares of stock or other securities of the Company or of another corporation (whether by reason of merger, consolidation, recapitalization, split-up, combination of shares, or otherwise), or the number of shares of Stock are changed through a stock split or the payment of a stock dividend, there shall be substituted for or added to each share of Stock theretofore reserved for sale and/or issuance under the Plan, the number and kind of shares of stock or other securities into which each outstanding share of Stock shall be so changed or converted, or for which each such share shall be exchanged, or to which each such share shall be entitled, as the case may be.

Section XVII — Amendment or Termination of the Plan

     The Board shall have the right to amend, modify or terminate the Plan at any time without notice; however, no Participant’s existing rights shall be adversely affected by any such amendment, modification or termination. In any event, any such amendment or modification that materially increases the benefits accruing to Participants under the Plan; or increases in any respect the number of shares of Stock permitted to be issued under the Plan; or materially modifies the eligibility requirements for Plan participation; or changes the designation of those corporations whose employees are eligible to participate in the Plan (other than another parent or subsidiary of the Company); shall not take affect, or otherwise become effective, until after such amendment or modification has received the approval of the holders of a majority of the voting power of the shares of Stock.

Section XVIII — Administration

     (a) Committee To Administer. The Plan shall be administered by a Committee, which shall be appointed by the Company’s president and consist of at least two employees of the Company or of a subsidiary corporation. The Committee shall be responsible for the administration of all matters under the Plan which have not been delegated to the Agent.

     (b) Specific Responsibilities. The Committee’s responsibilities shall include, but shall not be limited to,

     (i) interpreting the Plan (including issues relating to the definition and application of “Base Pay”);

     (ii) identifying and compiling a list of persons who are Eligible Employees for a Plan Year;

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(iii) identifying those Eligible Employees not entitled to be granted options or other rights for a Plan Year on account of the limitations described in Section III(b) hereof; and

(iv) providing prompt notice to the Agent of the enrollment of Eligible Employees, the amounts to be credited to Participants’ Plan Accounts, and any written notices of withdrawal or revocation of any authorization filed with the Committee by individual Participants.

The Committee may from time to time adopt rules and regulations for carrying out the Plan. Interpretation or construction of any provision of the Plan by the Committee shall be final, conclusive and binding on all persons, absent specific and contrary action taken by the Board. Any interpretation or construction of any provision of the Plan by the Board or a committee thereof shall be final, conclusive and binding.

Section XIX — Securities Law Restrictions

     Notwithstanding any provision of the Plan to the contrary:

     (a) Need For Registration Statement. No shares of Stock shall be purchased or issued under the Plan until a registration statement has been filed and become effective with respect to the issuance of the Stock covered by the Plan under the Securities Act of 1933, as amended (the “Act”). Prior to the effectiveness of such registration statement, Stock subject to purchase under the Plan may be offered to Eligible Employees only pursuant to an exemption from the registration requirements of the Act.

     (b) Compliance With Blue Sky Laws. No payroll deduction shall take place and no shares of Stock shall be purchased or issued under the Plan with respect to Eligible Employees resident in any state unless such shares of Stock are exempt from registration under the securities laws of such state, or such purchase or issuance constitutes an exempt transaction under the securities laws of such state or comprises part of a purchase or issuance that has been registered by description, qualification, coordination or otherwise under the securities laws of such state.

Section XX — No Independent Employment Rights

     Nothing in the Plan shall be construed to form, or to constitute evidence of, a contract of employment between the Company and any employee, or any group or category of employees (whether for a definite or specific duration or otherwise), or to prevent the Company, its parent or any subsidiary from terminating any employee’s employment at any time, without notice or recompense. No employee shall have any rights as a shareholder until the right to purchase Stock has been exercised as of the last trading day of a Subscription Period.

Section XXI — Agent Powers and Duties

     (a) Acceptance. The Agent accepts the agency created under this Plan and agrees to perform the obligations imposed hereunder.

     (b) Receipt of Shares and Dividends. The Agent shall be accountable to each Participant for shares of Stock held in such Participant’s Plan Account, and for dividends received with respect thereto.

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     (c) Records and Statements. The records of the Agent pertaining to the Plan shall be open to the inspection of the Company at all reasonable times and may be audited from time to time by any person or parties specified by the Company in writing. The Agent shall furnish the Company with whatever information relating to the Plan Accounts the Company considers necessary, including, without limitation, any information required to be furnished to Participants each January 31 pursuant to Section 6039(a)(2) of the Code and related regulations.

     (d) Fees and Expenses. The Agent shall receive from the Company reasonable annual compensation as may be agreed upon from time to time between the Company and the Agent.

     (e) Resignation. The Agent may resign at any time as Agent of the Plan by giving sixty (60) days written notice in advance to the Company.

     (f) Removal. The Company, by giving sixty (60) days written notice in advance to the Agent, may remove the Agent. In the event of the resignation or removal of an Agent, the Company shall promptly appoint a successor Agent, so long as it intends to continue the Plan.

     (g) Interim Duties and Successor Agent. Each successor Agent shall succeed to the title of the Agent vested in its predecessor by accepting in writing its appointment as successor Agent and filing the acceptance with the former Agent and the Company without the signing or filing of any further statement. The resigning or removed Agent, upon receipt of acceptance in writing of the agency by the successor Agent, shall execute all documents and do all acts necessary to vest the title in any successor Agent. Each successor Agent shall have and enjoy all of the powers conferred under this Plan upon its predecessor. No successor Agent shall be personably liable for any act or failure to act of any predecessor Agent. With the approval of the Company, a successor Agent, with respect to the Plan, may accept the account rendered and the property delivered to it by a predecessor Agent without incurring any liability or responsibility for so doing.

     (h) Limitation of Liability to Participants. The Agent shall not be liable hereunder for any act or failure to act, including without limitation, any claim of liability (i) arising out of a failure to terminate a Participant’s Plan Account upon such Participant’s death or adjudication of incompetency, prior to the receipt by the Agent of notice in writing of such death or incompetency; or (ii) with respect to the price(s) at which shares of Stock are purchased or sold for a Participant’s Plan Account, or the timing of any such purchase(s) or sale(s).

Section XXII — Applicable Law

     The Plan shall be construed, administered and governed in all respects under the laws of the State of Ohio.

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Attachment A

to

KEITHLEY INSTRUMENTS, INC.
1993 EMPLOYEE STOCK PURCHASE AND DIVIDEND REINVESTMENT PLAN

List of Participating Subsidiary Corporations

Keithley Instruments, GMBH

Keithley Instruments, Ltd.

Keithley Instruments, SARL

Keithley Instruments, BV

Keithley Instruments, Srl

Keithley Instruments, KK

Keithley Instruments, SA

Keithley Instruments International Corporation

Keithley Instruments Sdn Bhd

Page 10

EX-5.1

Exhibit 5.1

Baker & Hostetler LLP

3200 National City Center
1900 East 9th Street
Cleveland, OH 44114-3485

T 216.661.0200
F 216.696.0740
www.bakerlaw.com

June 14, 2006

Keithley Instruments, Inc.
28775 Aurora Road
Cleveland, Ohio 44139

Ladies and Gentlemen:

We have acted as counsel to Keithley Instruments, Inc., an Ohio corporation (the “Company”), in connection with its Registration Statement on Form S-8 (the “Registration Statement”), filed under the Securities Act of 1933, as amended, relating to the offering of up to 500,000 Common Shares, without par value of the Company (the “Common Shares”), pursuant to the Company’s 2005 Employee Stock Purchase and Dividend Reinvestment Plan (the “Plan”).

In connection with the foregoing, we have examined (a) the Amended Articles of Incorporation and the Amended Code of Regulations of the Company, (b) the Plan, and (c) such records of the corporate proceedings of the Company and such other documents as we deemed necessary to render this opinion.

Based on such examination, we are of the opinion that:

1. The Company is a corporation duly organized and validly existing under the laws of the State of Ohio.

2. The Common Shares available for issuance under the Plan, when issued and sold pursuant to the Plan, will be legally issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as Exhibit 5.1 to the Registration Statement.

Sincerely,

/s/ Baker & Hostetler LLP

Baker & Hostetler LLP

Cincinnati    Cleveland    Columbus    Costa Mesa    Denver    Houston    Los Angeles    New York    Orlando    Washington, DC

EX-23.1

Exhibit 23.1

Consent of PricewaterhouseCoopers LLP

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in the Registration Statement on Form S-8 of our report dated December 13, 2005 relating to the financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, which is incorporated by reference in Keithley Instruments, Inc.’s Annual Report on Form 10-K for the year ended September 30, 2005.

/s/ PricewaterhouseCoopers LLP

Cleveland, Ohio
June 14, 2006