SCHEDULE 14A INFORMATION

                  Proxy Statement Pursuant to Section 14(a) of
                      the Securities Exchange Act of 1934

    Filed by the Registrant / /
    Filed by a Party other than the Registrant /X/

    Check the appropriate box:
    / /  Preliminary Proxy Statement
    / /  Confidential, for Use of the Commission Only (as permitted by Rule
         14a-6(e)(2))
    / /  Definitive Proxy Statement
    /X/  Definitive Additional Materials
    / /  Soliciting Material Pursuant to Section240.14a-11(c) or
         Section240.14a-12

                                QUICKTURN DESIGN SYSTEMS, INC.
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                (Name of Registrant as Specified In Its Charter)

                                 MENTOR GRAPHICS CORPORATION
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    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)
 
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            MENTOR GRAPHICS EXTENDS TENDER OFFER FOR
                   QUICKTURN DESIGN SYSTEMS


WILSONVILLE, OR, DECEMBER 3, 1998 -- Mentor Graphics Corporation (Nasdaq: MENT)
today announced that it has extended its $12.125 per share cash tender offer 
for all outstanding shares of the common stock of Quickturn Design Systems, 
Inc. (Nasdaq: QKTN) to 12:00 Midnight, New York City time, on Monday,
January 11, 1999, unless extended.

The tender offer has been extended to three days after the special meeting of 
Quickturn's stockholders which will be held on January 8, 1999 as a result of 
the decision on December 2, 1998 by the Delaware Court of Chancery. The 
record date for stockholders to vote in the special meeting is November 10, 
1998.

As of the close of business on December 3, 1998, 9,229,265 shares of 
Quickturn common stock had been validly tendered into the Offer, which, 
together with the 591,500 shares already owned by Mentor, represents 
approximately 54.0 percent of Quickturn's outstanding common stock (based 
upon 18,077,059 shares outstanding as of October 31, 1998). The shares 
tendered represent 51.0 percent of the outstanding common stock.

Mentor's Offer to Purchase, proxy solicitation materials and related documents
are available on a Mentor World Wide Web site at http://www.mentorg.com/file.

The Dealer Manager for the Offer is Salomon Smith Barney.  The Information
Agent for the Offer is MacKenzie Partners, Inc., which can be reached toll-free
at 800-322-2885 or by collect call at 212-929-5500.

Contacts:    Ry Schwark                      Roy Winnick/Todd Fogarty
             Director of Public Relations    Kekst and Company
             503/685-1660                    212/521-4800


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