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 * PENDERGRASS LARRY L   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 New Product Development (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)   6,533 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 Share Option

$ 12.43

12/08/2010

D(2)

20,000

05/20/2005(3)

05/19/2013

Common Shares

20,000

$ 9.17

0

D

Common Share Option

$ 18.75

12/08/2010

D(4)

25,000

02/15/2005(5)

07/16/2014

Common Shares

25,000

$ 2.85

0

D

Common Share Option

$ 15.05

12/08/2010

D(6)

8,800

10/04/2007(3)

10/03/2015

Common Shares

8,800

$ 6.55

0

D

Common Share Option

$ 14

12/08/2010

D(7)

9,600

01/30/2009(3)

01/30/2017

Common Shares

9,600

$ 7.6

0

D

Common Share Option

$ 9.12

12/08/2010

D(8)

8,300

11/09/2009(3)

11/09/2017

Common Shares

8,300

$ 12.48

0

D

Common Share Option

$ 2.99

12/08/2010

D(9)

17,400

02/06/2011(3)

02/06/2019

Common Shares

17,400

$ 18.61

0

D

Restricted Unit Award

$ 0

12/08/2010

D(10)

5,800

(11)

(11)

Common Shares

5,800

$ 21.6

0

D

Common Share Option

$ 4.26

12/08/2010

D(12)

13,200

12/04/2011(3)

12/04/2019

Common Shares

13,200

$ 17.34

0

D

Performance Award Unit

$ 0

12/08/2010

D(10)

6,600

09/30/2012(13)

(13)

Common Shares

6,600

$ 21.6

0

D

Restricted Unit Award

$ 0

12/08/2010

D(10)

4,400

(14)

(14)

Common Shares

4,400

$ 21.6

0

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
PENDERGRASS LARRY L KEITHLEY INSTRUMENTS, INC. 28775 AURORA ROAD SOLON, OH 44139			VP New Product Development

Signatures

Mark J. Plush, Attorney-in Fact		12/10/2010
**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 $12.43.
(3)	Date reported applies to 50% of total, one-half of the balance is then exercisable in each succeeding year.
(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 $18.75.
(5)	Option became fully vested on February 15, 2005
(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 $15.05.
(7)	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 $14.00.
(8)	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 $9.12.
(9)	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 $2.99.
(10)	The units were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share.
(11)	Restricted unit awards were to become fully vested on February 6, 2013. Common shares represented by such vested restricted unit awards were to be delivered promptly after such vesting date.
(12)	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 $4.26.
(13)	Each Performance Award Unit represented a right to receive one common share. The number of units comprising the initial award were to be adjusted (ranging from a maximum of twice the number of units comprising the initial award, to a minimum of no units), based on award program metrics that compare the Company's total shareholder return performance occurring during the Measurement Period to comparable total shareholder return performance reported by companies in the Russell Microcap Index. Awarded units earned based on these metrics as of September 30, 2012 (the vesting date) were to be converted to shares under the Plan and will be issued on or before December 31, 2012.
(14)	Restricted unit awards were to become fully vested on December 4, 2013. Common Shares represented by such vested restricted unit awards were to be delivered promptly after such vesting date.

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