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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1. Name and Address of Reporting Person * REDDY N MOHAN   2. Issuer Name and Ticker or Trading Symbol KEITHLEY INSTRUMENTS INC [KEI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) KEITHLEY INSTRUMENTS, INC., 28775 AURORA ROAD 3. Date of Earliest Transaction (Month/Day/Year) 12/08/2010 (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 12/08/2010   D(1)   35,507 D $ 21.6 0 D

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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 Stock Option

$ 13.465

12/08/2010

D(2)

5,000

03/21/2002

09/20/2011

Common Stk

5,000

$ 8.135

0

D

Common Stock Option

$ 19.23

12/08/2010

D(3)

10,000

08/17/2002

02/16/2012

Common Stk

10,000

$ 2.37

0

D

Common Stock Option

$ 10.7

12/08/2010

D(4)

10,000

08/16/2003

02/15/2013

Common Stk

10,000

$ 10.9

0

D

Common Stock Option

$ 23.13

12/08/2010

D(5)

10,000

08/15/2004

02/14/2014

Common Stk

0

$ 0

0

D

Common Stock Option

$ 16.67

12/08/2010

D(6)

10,000

05/13/2005

02/12/2015

Common Stk

10,000

$ 4.93

0

D

Phantom Stock Units

(7)

12/08/2010

D(8)

32,061.2

(8)

(8)

Common Stk

32,061.2

$ 21.6

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
REDDY N MOHAN KEITHLEY INSTRUMENTS, INC. 28775 AURORA ROAD SOLON, OH 44139	X

Signatures

Mark J. Plush, Attorney-in Fact		12/09/2010
**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)	Disposed of pursuant to an Agreement and Plan of Merger, dated as of September 29, 2010 (the "Merger Agreement") by and among Danaher Corporation, Aegean Acquisition Corp. and the Issuer in exchange for the merger consideration of $21.60 in cash per share.
(2)	The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $13.465.
(3)	The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $19.23.
(4)	The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $10.70.
(5)	The options were cancelled pursuant to the Merger Agreement.
(6)	The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $16.67.
(7)	Phantom shares were acquired on various dates (beginning 12/10/2001)with prices ranging from $3.2412 to $23.3575.
(8)	The phantom stock units were accrued under the Keithley Instruments, Inc. Deferred Stock Plan and were to be settled in common stock or cash upon the retirement from the Board of the reporting person. The plan was terminated and liquidated at closing of the merger and, under the Merger Agreement, the Phantom Stock Units were cancelled in exchange for the merger consideration of $21.60 in cash per share.

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