UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of Earliest Event Reported):                 April 28, 2009


                           Keithley Instruments, Inc.
             ------------------------------------------------------
             (Exact name of registrant as specified in its charter)

        Ohio                         1-9965                     34-0794417
- ---------------------            --------------               --------------
  (State or other                 (Commission                (I.R.S. Employer
   jurisdiction                   File Number)              Identification No.)
 of incorporation)


     28775 Aurora Road, Solon, Ohio                                44139
   ---------------------------------                            -----------
(Address of principal executive offices)                         (Zip Code)

    Registrant's telephone number, including area code:      (440) 248-0400


                                 Not Applicable

           -----------------------------------------------------------
           Former name or former address, if changed since last report



Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

[ ]  Written communications pursuant to Rule 425 under the Securities Act (17
     CFR 230.425)

[ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
     240.14a-12)

[ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
     Exchange Act (17 CFR 240.14d-2(b))

[ ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
     Exchange Act (17 CFR 240.13e-4(c))


Item 1.01 Entry into a Material Definitive Agreement.

On April 28, 2009, Keithley Instruments, Inc. (the "Company") and JPMorgan Chase
Bank, N.A. entered into the Sixth Amendment (the "Amendment") to the Credit
Agreement, dated as of March 30, 2001, as amended (the "Credit Agreement"), and
a Pledge, Assignment and Security Agreement (the "Pledge Agreement"). The
Amendment has an effective date of March 31, 2009 and reduced the available
borrowing under the Credit Agreement from $10.0 million to $5.0 million. The
Amendment also eliminated the debt covenants from the Credit Agreement, requires
cash to be pledged against outstanding borrowings pursuant to the Pledge
Agreement, changed the applicable interest rate for outstanding borrowings to
either LIBOR plus 0.75% or 2.5% depending on the timeframe of the borrowing and
changed the facility fee to 0.25% on the total amount of the commitment. The
March 31, 2011 expiration date remains unchanged.

Copies of the Amendment and the Pledge Agreement will be filed with the
Company's Form 10-Q for the quarter ended March 31, 2009.




                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                            Keithley Instruments, Inc.

May 4, 2009                                 By:    /s/ Mark J. Plush
                                                   ---------------------------

                                                  Name: Mark J. Plush
                                                  Title: Vice President and
                                                         Chief Financial Officer