FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * PESEC JOHN A   2. Issuer Name and Ticker or Trading Symbol KEITHLEY INSTRUMENTS INC [KEI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) VP Worldwide Sales & Support (Last) (First) (Middle) KEITHLEY INSTRUMENTS, INC., 28775 AURORA ROAD 3. Date of Earliest Transaction (Month/Day/Year) 07/29/2008 (Street) SOLON, OH 44139 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Shares 06/30/2008   J(1)   28 A $ 9.67 7,236 D   Common Shares 07/29/2008   M   12,000 A $ 4.125 19,236 D   Common Shares 07/29/2008   S   12,000 D $ 9.9992 (2) 7,236 D   Common Shares               10 I Jointly held with wife Common Shares               9 I Wife

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Common Share Option

$ 4.125

07/29/2008

M

12,000

07/17/2001

07/16/2009

Common Shares

12,000

$ 0

0

D

Common Share Option

$ 45.125

08/02/2002(3)

08/01/2010

Common Shares

11,000

11,000

D

Common Share Option

$ 18.41

07/25/2003(3)

07/24/2011

Common Shares

25,000

25,000

D

Common Share Option

$ 13.76

07/24/2004(3)

07/23/2012

Common Shares

27,000

27,000

D

Common Share Option

$ 16.12

08/10/2005(4)

07/18/2013

Common Shares

30,000

30,000

D

Common Share Option

$ 18.75

02/15/2005(5)

07/16/2014

Common Shares

26,000

26,000

D

Common Share Option

$ 15.05

10/04/2007(3)

10/03/2015

Common Shares

10,000

10,000

D

Performance Award Unit

$ 0

09/30/2008(6)

(6)

Common Shares

7,700 (6)

7,700 (6)

D

Common Share Option

$ 14

01/30/2009(3)

01/30/2017

Common Shares

10,000

10,000

D

Performance Award Unit

$ 0

09/30/2009(6)

(6)

Common Shares

7,700 (6)

7,700 (6)

D

Common Share Option

$ 9.12

11/09/2009(3)

11/09/2017

Common Shares

7,500

7,500

D

Performance Award Unit

$ 0

09/30/2010(6)

(6)

Common Shares

5,700 (6)

5,700 (6)

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
PESEC JOHN A KEITHLEY INSTRUMENTS, INC. 28775 AURORA ROAD SOLON, OH 44139			VP Worldwide Sales & Support

Signatures

Mark J. Plush, Attorney-in Fact		07/30/2008
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Acquired through Employee Stock Purchase and Dividend Reinvestment Plan.
(2)	Average sales price of $9.9992 used (prices ranged from $9.91 to $10.08)
(3)	Date reported applies to 50% of total, one-half of the balance is then exercisable in each succeeding year.
(4)	Option became fully vested on August 10, 2005
(5)	Option became fully vested on February 15, 2005
(6)	Each Performance Award Unit represents the right to receive one common share. The number of units initially awarded, the target, is shown above. The actual number of units that will be awarded and converted to shares is based upon: a) the Company's revenue growth as compared to a defined Peer Group and, b) the Company maintaining an acceptable level of profitability during the performance period which ends on the date exercisable (the "vesting date"). Awarded units are automatically converted to shares under the Plan on or before the December 31st following the Vesting Date.

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