Exhibit 99.1
 
                                  OrCAD, INC.

          THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS


         The undersigned stockholder of OrCAD, Inc., a Delaware corporation (the
"Company"), hereby appoints Michael F. Bosworth and P. David Bundy, or either of
them, with full power of substitution in each, as proxies to cast all votes
which the undersigned stockholder is entitled to cast at the Special Meeting of
Stockholders (the "Special Meeting") to be held at 10:00 a.m. local time, on
Tuesday, December 30, 1997 at the Crowne Plaza, 4811 Kruse Oaks Blvd., Lake 
Oswego, Oregon 97035, and any adjournments or postponements thereof upon the
matters listed herein.

         1.       Approval of the issuance of shares of common stock of the
                  Company to the shareholders of MicroSim Corporation
                  ("MicroSim") in connection with an Agreement and Plan of
                  Merger, dated as of October 13, 1997, by and among the
                  Company, OCA Merger Corporation, an Oregon corporation and a
                  wholly owned subsidiary of the Company ("Merger Sub") and
                  MicroSim, which provides for the merger of Merger Sub into
                  MicroSim.

                   FOR            AGAINST            ABSTAIN
                   ---            -------            -------

                   [_]              [_]                [_]



         2.       In their discretion,the proxies are authorized to vote upon 
                  such matters as may properly come before the meeting or any
                  adjournments or postponements thereof.

          (Continued, and to be signed and dated on the reverse side)


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                          (Continued from reverse side)

PLEASE SIGN, DATE AND RETURN THIS PROXY CARD TODAY, USING THE ENCLOSED ENVELOPE.

THIS PROXY, WHEN PROPERLY EXECUTED, WILL BE VOTED IN THE MANNER DIRECTED HEREIN
BY THE UNDERSIGNED STOCKHOLDER. UNLESS DIRECTION IS GIVEN, THIS PROXY WILL BE
VOTED FOR PROPOSAL 1 AND IN ACCORDANCE WITH THE RECOMMENDATIONS OF A MAJORITY OF
THE BOARD OF DIRECTORS AS TO OTHER MATTERS. The undersigned hereby acknowledges
receipt of the Company's Proxy Statement and hereby revokes any proxy or proxies
previously given.

Please sign below exactly as your name appears on this Proxy Card. If shares are
registered in more than one name, the signatures of all such persons are
required. A corporation should sign in its full corporate name by a duly
authorized officer, stating his/her title. Trustees, guardians, executors and
administrators should sign in their official capacity, giving their full title
as such. If a partnership, please sign in the partnership name by authorized
person(s).

If you receive more than one Proxy Card, please sign and return all such cards
in the accompanying envelope.



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                                Typed or Printed Name(s)


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                                Authorized Signature


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                                Title or Authority, if Applicable


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                                Date