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                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
 
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                                 SCHEDULE 14D-9
                               (AMENDMENT NO. 30)
 
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               Solicitation/Recommendation Statement Pursuant to
            Section 14(d)(4) of the Securities Exchange Act of 1934
 
                         QUICKTURN DESIGN SYSTEMS, INC.
                           (Name of Subject Company)
 
                         QUICKTURN DESIGN SYSTEMS, INC.
                      (Name of Person(s) Filing Statement)
 
                    COMMON STOCK, PAR VALUE $.001 PER SHARE
           (including the associated preferred stock purchase rights)
                         (Title of Class of Securities)
 
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                                   74838E102
                     (CUSIP Number of Class of Securities)
 
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                                 KEITH R. LOBO
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                         QUICKTURN DESIGN SYSTEMS, INC.
                               55 W. TRIMBLE ROAD
                           SAN JOSE, CALIFORNIA 95131
                                 (408) 914-6000
      (Name, address and telephone number of person authorized to receive
       notice and communications on behalf of person(s) filing statement)
 
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                                    COPY TO:
 
                             LARRY W. SONSINI, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                               650 PAGE MILL ROAD
                        PALO ALTO, CALIFORNIA 94304-1050
                                 (650) 493-9300
 
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                                 INTRODUCTION
 
  The Solicitation/Recommendation Statement on Schedule 14D-9 (the "Schedule
14D-9") originally filed on August 24, 1998, by Quickturn Design Systems,
Inc., a Delaware corporation (the "Company" or "Quickturn"), relates to an
offer by MGZ Corp., a Delaware corporation ("MGZ") and a wholly owned
subsidiary of Mentor Graphics Corporation, an Oregon corporation ("Mentor"),
to purchase all of the outstanding shares of the common stock, par value $.001
per share (including the associated preferred stock purchase rights), of the
Company. All capitalized terms used herein without definition have the
respective meanings set forth in the Schedule 14D-9.
 
ITEM 8. ADDITIONAL INFORMATION TO BE FURNISHED
 
  The response to Item 8 is hereby amended by adding the following to the end
of the section entitled "Proxy Solicitation":
 
  On December 24, 1998, the Company issued a press release and sent a letter,
revised proxy card, and addendum to the Company's proxy statement in
opposition to the solicitation by Mentor and MGZ. A copy of the press release,
letter, addendum to proxy statement, and revised proxy card are filed as
Exhibits 61, 62, 63 and 64, respectively, hereto, and are incorporated herein
by reference.
 
ITEM 9. MATERIAL TO BE FILED AS EXHIBITS
 
  The response to Item 9 is hereby amended by the addition of the following
new exhibit:
 

           
   Exhibit 61 Press Release of the Company dated December 24, 1998.
   Exhibit 62 Letter to the Company's Stockholders dated December 24, 1998.
   Exhibit 63 Addendum to Proxy Statement dated December 24, 1998.
   Exhibit 64 Revised Proxy Card.

 
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                                   SIGNATURE
 
  After reasonable inquiry and to the best of its knowledge and belief, the
undersigned certifies that the information set forth in this statement is
true, complete and correct.
 

                                          
 Dated: December 24, 1998                    QUICKTURN DESIGN SYSTEMS, INC.

 
                                              /s/ Keith R. Lobo
                                          By: _________________________________
                                              Keith R. Lobo
                                              President and Chief Executive
                                               Officer
 
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