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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM 4

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

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

1.	Name and Address of Reporting Person* (Last, First, Middle)	2.	Issuer Name and Ticker or Trading Symbol				3.	I.R.S. Identification Number of Reporting Person, if an entity (Voluntary)
	Plush, Mark J		Keithley Instruments, Inc. (KEI)
	5205 Ramblewood Court	4.	Statement for (Month/Day/Year)				5.	If Amendment, Date of Original (Month/Day/Year)
			April 25, 2003
	(Street)	6.	Relationship of Reporting Person(s) to Issuer (Check All Applicable)				7.	Individual or Joint/Group Filing (Check Applicable Line)
	Solon, OH 44139 (City)                (State)           (Zip)		o	Director	o	10% Owner		x	Form filed by One Reporting Person
			x	Officer (give title below)				o	Form filed by More than One Reporting Person
			o	Other (specify below)
				VP & CFO

Reminder:	Report on a separate line for each class of securities beneficially owned directly or indirectly.
*	If the form is filed by more than one reporting person, see instruction 4(b)(v).

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 Transactions(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

12/31/02

J

V

2

A

12.55

Common Shares

1/3/03

J

V

282

A

10.625

Common Shares

3/31/03

J

V

4

A

10.543

Common Shares

4/25/03

G

V

180

D

44,092

D

Restristed Common Shares*

23,836

D

Common Shares

12/31/02

J

V

4

A

12.559

Common Shares

3/31/03

J

V

4

A

10.56

1,224

I

Trust (1)

Common Shares

12/31/02

J

V

4

A

12.559

Common Shares

3/31/03

J

V

4

A

10.56

1,224

I

Trust (2)

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)

Code

V

(A)

(D)

Common Stock Option

$5.71875

9/19/97

Common Stock Option

$2.53125

9/11/98

Common Stock Option

$4.125

7/16/99

Common Stock Option

$45.125

8/1/00

Common Stock Option

$18.41

7/24/01

Common Stock Option

$13.76

7/23/02

Page 3

Table II — Derivative Securities Acquired, Disposed of, or Beneficially Owned — Continued (e.g., puts, calls, warrants, options, convertible securities)
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)
	Date Exercisable	Expiration Date		Title	Amount or Number of Shares
	9/20/99(3)	9/19/07(3)		Common Stk	7,000			$ -			7,000		D
	9/12/00(3)	9/11/08(3)		Common Stk	23,000			$ -			23,000		D
	7/17/01(3)	7/16/09(3)		Common Stk	40,000			$ -			40,000		D
	8/2/02(3)	8/1/10(3)		Common Stk	42,000			$ -			42,000		D
	7/25/03(3)	7/24/11(3)		Common Stk	38,000			$ -			38,000		D
	7/24/04(3)	7/23/12(3)		Common Stk	35,000			$ -			35,000		D

Explanation of Responses:

(1) Martin J. Plush Trust, Virginia A. Plush Trustee

(2) Christopher M. Plush Trust, Virginia A. Plush Trustee

(3) Date reported applies to 50% of total, one-half of the balance is then exercisable in each succeeding year

*Restricted Shares will become fully vested on June 1, 2011

J - Acquired through Employee Stock Purchase and Dividend Reinvestment Plan

Mark J. Plush	4/28/03
**Signature of Reporting Person	Date

**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

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