Ownership Submission
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 *
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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