1 EXHIBIT 22.1 PRESENT SUBSIDIARIES PERCENTAGE STATE OR OF VOTING JURISDICTION OF SECURITIES INCORPORATION OWNED --------------------- ---------- Teradyne BeneLux, Inc (Ltd.)............................ Delaware 100% Teradyne Canada Limited................................. Canada 100% Teradyne GmbH........................................... West Germany 100% Teradyne Holdings Limited............................... England 100% Teradyne Limited................................... England 100% Teradyne Hong Kong, Ltd................................. Delaware 100% Teradyne International, Ltd............................. U.S. Virgin Islands 100% Teradyne Ireland Limited................................ Ireland 100% Teradyne Italia S.r.l................................... Italy 100% Teradyne Japan, Ltd..................................... Delaware 100% Teradyne K.K....................................... Japan 100% Teradyne Korea, Ltd..................................... Delaware 100% Teradyne Leasing, Inc................................... Massachusetts 100% Teradyne Malaysia, Ltd.................................. Delaware 100% Teradyne Netherlands B.V................................ Netherlands 100% Teradyne Netherlands, Ltd............................... Delaware 100% Teradyne Realty, Inc.................................... Massachusetts 100% Teradyne S.A............................................ France 100% Teradyne Scandinavia, Inc............................... Delaware 100% Teradyne Software and Systems Test, Inc................. Delaware 100% Teradyne Singapore, Ltd................................. Delaware 100% Teradyne Taiwan, Ltd.................................... Delaware 100% Zehntel Holdings, Inc................................... California 100% Zehntel, SARL...................................... France 100% 1000 Washington, Inc.................................... Massachusetts 100% 31