1 21. Subsidiaries of the registrant WHOLLY OWNED SUBSIDIARIES Keithley International Investment Corporation 28775 Aurora Road, Cleveland, Ohio 44139, U.S.A. Keithley Foreign Sales Corporation 5 Norre Gade, Charlotte Amalie St. Thomas, U.S. Virgin Islands 00801 FRANCE: Keithley Instruments SARL BP 60, 3 allee des Garays 91122 Palaiseau Cedex GERMANY: Keithley Instruments GmbH Landsberger Strasse 65 82110 Germering (Munich) GREAT BRITAIN: Keithley Instruments Ltd. The Minister, 58 Portman Road Reading (London), Berkshire RG30 1EA ITALY: Keithley Instruments SRL Viale San Gimignano 38 20146 Milano JAPAN: Keithley Instruments Far East KK Aibido Building 7-20-2 Nishishinjuku Shinjuku-ku, Tokyo 160 NETHERLANDS: Keithley Instruments BV Avenlingen West 49 4202 MS Gorinchem (Amsterdam) SWITZERLAND: Keithley Instruments SA Kriesbachstrasse 4 8600 Dubendorf (Zurich)