EXHIBIT 21 MENTOR GRAPHICS' SUBSIDIARIES The following is a list of wholly owned direct or indirect subsidiaries of Mentor Graphics Corporation as of December 31, 1998. Anacad Electrical Engineering S.a.r.l (France) Antares Corporation Exemplar Logic, Inc. Exemplar Logic (Europe) Limited Mentor Graphics (Canada) Ltd. Mentor Graphics (Denmark) A/S Mentor Graphics (Finland) OY Mentor Graphics (France) S.a.r.l. Mentor Graphics (Egypt) Mentor Graphics (Schweiz) AG Switzerland Mentor Graphics (Singapore) PTE. LTD. Mentor Graphics (Taiwan) Co. Ltd. Mentor Graphics (UK) Ltd. Mentor Graphics Design S.A. (Spain) SA Mentor Graphics Deutschland (GmbH) Mentor Graphics (Finance) B.V. Mentor Graphics Israel Ltd. Mentor Graphics Japan Co. Ltd. Mentor Graphics Netherlands B.V. Mentor Graphics Scandinavia AB Mentor Graphics (Sophia-Antipolis) EURL Mentor Graphics (India) Pvt. Ltd. Mentor Graphics (Ireland) Limited Mentor Korea Company Meta Systems S.A. Model Technology Inc.