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                                SCHEDULE 14A
                               (RULE 14a-101)
                   INFORMATION REQUIRED IN PROXY STATEMENT
                          SCHEDULE 14A INFORMATION


          PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES
                            EXCHANGE ACT OF 1934
        
Filed by the Registrant [X]

Filed by a Party other than the Registrant [_] 

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 

[_]  Definitive Additional Materials 

[X]  Soliciting Material Pursuant to Section 240.14a-11(c) or Section 240.14a-12

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


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   (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

   
Payment of Filing Fee (Check the appropriate box):

[X]  No fee required.

[_]  Fee computed on table below per Exchange Act Rules 14a-6(i)(4) and 0-11.

   
     (1) Title of each class of securities to which transaction applies:

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     (2) Aggregate number of securities to which transaction applies:

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     (3) Per unit price or other underlying value of transaction computed
         pursuant to Exchange Act Rule 0-11 (Set forth the amount on which
         the filing fee is calculated and state how it was determined):

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     (4) Proposed maximum aggregate value of transaction:

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     (5) Total fee paid:

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[_]  Fee paid previously with preliminary materials.
     
[_]  Check box if any part of the fee is offset as provided by Exchange
     Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee
     was paid previously. Identify the previous filing by registration statement
     number, or the Form or Schedule and the date of its filing.
     
     (1) Amount Previously Paid:
 
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     (2) Form, Schedule or Registration Statement No.:

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     (3) Filing Party:
      
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     (4) Date Filed:

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Notes:




 
                       [LOGO OF QUICKTURN APPEARS HERE]

                                                               September 4, 1998

Dear Stockholder:

     I am writing to you about an urgent matter concerning the future of your
investment in Quickturn Design Systems, Inc.

     You may have received, or will likely soon receive, a communication from
Mentor Graphics Corporation attempting to solicit from you agent designations in
an attempt to call a special meeting of stockholders of Quickturn as a first
step in the implementation of their inadequate $12.125 per share tender offer.
Your Board of Directors will soon send to you a full package of its own
solicitation materials.  We strongly recommend that you wait until receiving
these materials before doing anything.  This package will also provide you with
the opportunity to reconsider any agent designation card you may have sent to
Mentor.  After careful consideration of the Mentor offer, your Board of
Directors has determined that the Mentor offer is inadequate and not in the best
interests of the Company's stockholders, that the Mentor offer does not fully
reflect the long-term value of the Company, and that stockholder interests would
be better served by the Company continuing to pursue its business plan.

                      THERE IS ABSOLUTELY NO NEED FOR YOU
                        TO TAKE ANY ACTION AT THIS TIME

     Mentor's rush to seek your agent designation to call a special meeting is
nothing more than a pressure tactic to carry out its opportunistic, hostile
takeover of Quickturn.

           DO NOT BE STAMPEDED BY MENTOR'S ATTEMPT TO SOLICIT YOUR 
               VOTE BEFORE YOU HEAR FROM YOUR BOARD OF DIRECTORS

     Again, we urge stockholders not to take any action until you have received
our materials, and not to execute any GREEN Mentor agent designation at this
time.  If you have any questions about this process or need further assistance,
please contact our proxy solicitor:

                                MORROW & CO., AT
                          1 (800) 566-9061 (TOLL-FREE)

     We have every confidence in our Company's future and wish to reaffirm our
determination that you, our stockholders, be given every opportunity to
participate fully in that future.  Your Board of Directors and I greatly
appreciate your continued support and encouragement.

                              Very truly yours,

                              /s/ KEITH R. LOBO
                              Keith R. Lobo
                              PRESIDENT AND CHIEF EXECUTIVE OFFICER

 
     The following is a list of the names and stock holdings of individuals who
may be deemed to be "participants" in the solicitation of proxies or revocation
of agent designations by Quickturn Design Systems, Inc. in opposition to Mentor
Graphics's solicitation of agent designations to call a special meeting of
stockholders (information with respect to stockholdings includes common stock
and stock issuable pursuant to options exercisable within 60 days): Richard C.
Alberding (17,500); Glen M. Antle (325,782); Michael R. D'Amour (40,971);
William A. Hasler (3,667); Dr. Yen-Son (Paul) Huang (354,550), Charles D.
Kissner (1,667); Dr. David K. Lam (10,417); Keith R. Lobo (438,750); Michael
Ferguson (none); Jeffrey K. Jordan (1,134), Donald J. McInnis (369,051); Raymond
K. Ostby (102,767); Dugald H. Stewart (7,390); Christopher J. Tice (22,802);
Tung-sun Tung (34,665); Naeem Zafar (34,713).