EXHIBIT 16.1 [LETTERHEAD OF PRICE WATERHOUSE LLP] November 22, 1995 Securities and Exchange Commission 450 5th Street, N.W. Washington, D.C. 20549 Ladies and Gentlemen: Parametric Technology Corporation --------------------------------- We have read Item 4 of Parametric Technology Corporations Form 8-K dated November 17, 1995 and are in agreement with the statements contained in paragraph 4(a) therein. Yours very truly, /S/ Price Waterhouse LLP Price Waterhouse LLP