EXHIBIT 21 TELLABS, INC. AND SUBSIDIARIES SUBSIDIARIES OF THE REGISTRANT AS OF MARCH 27, 1995 State or Other Jurisdiction of Name Incorporation Tellabs Operations, Inc. Delaware Tellabs Export, Inc. Delaware Tellabs Caribe, Inc. Delaware Telecommunications Laboratories, Inc. Illinois Tellabs International, Inc. Illinois Tellabs Communications Canada Ltd. Ontario, Canada Tellabs (V.I.), Inc. U.S. Virgin Islands Tellabs H.K. Ltd. Hong Kong Tellabs NZ Limited New Zealand Tellabs Korea, Inc. Korea Tellabs PTY. Ltd. Australia Tellabs Holdings Ltd. Ireland Tellabs Ltd. Ireland Tellabs (Ireland) Ltd. Ireland Tellabs Research Ltd. Ireland Tellabs SA Belgium Tellabs U.K. Ltd. United Kingdom Tellabs GmbH Germany Tellabs Mexico, Inc. Delaware Tellabs de Mexico, S.A. de C.V. Mexico Martis Oy Finland