EXHIBIT 32(a)

                Certification Pursuant to 18 U.S.C. Section 1350

      I, Joseph P. Keithley, Chairman, President and Chief Executive Officer of
Keithley Instruments, Inc. (the "Company"), certify, pursuant to 18 U.S.C.
Section 1350, that:

      (1) The Annual Report on Form 10-K of the Company for the period ended
      September 30, 2005 which this certification accompanies fully complies
      with the requirements of section 13(a) or 15(d) of the Securities Exchange
      Act of 1934; and

      (2) The information contained in the Report fairly presents, in all
      material respects, the financial condition and results of operations of
      the Company.

/s/ Joseph P. Keithley
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Joseph P. Keithley
Chairman, President and Chief Executive Officer
December 13, 2005

A signed original of this written statement has been provided to Keithley
Instruments, Inc. and will be retained by Keithley Instruments, Inc. and
furnished to the Securities and Exchange Commission or its staff upon request.