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.