1 EXHIBIT 23.1 CONSENT OF KPMG PEAT MARWICK LLP The Board of Directors Synopsys, Inc. We consent to incorporation herein by reference of our report dated October 17, 1997, relating to the consolidated balance sheets of Synopsys, Inc. and subsidiaries as of September 30, 1996 and 1997, and the related consolidated statements of income, stockholders' equity, and cash flows for each of the years in the three-year period ended September 30, 1997, and the related schedule, which reports appear in the September 30, 1997, annual report on Form 10-K of Synopsys, Inc. KPMG PEAT MARWICK LLP /s/KPMG PEAT MARWICK LLP Mountain View, California August 3, 1998