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Exhibit (a)(3)
 (COMPUTERSHARE LOGO)   Form of Proxy  Special Meeting to be held on February 18, 2005   This Form of Proxy is solicited by and on behalf of Management.
 Notes to proxy
 1.
    
    Every holder has the right to appoint some other person of their choice, who need not be a
holder, to attend and act on their behalf at the meeting. If you wish to appoint a person
other than the persons whose names are printed herein, please insert the name of your chosen
proxyholder in the space provided (see reverse).2.
    
    If the securities are registered in the name of more than one owner (for example, joint
ownership, trustees, executors, etc.), then all those registered should sign this proxy. If
you are voting on behalf of a corporation or another individual you may be required to provide
documentation evidencing your power to sign this proxy with signing capacity stated.3.
    
    This proxy should be signed in the exact manner as the name appears on the proxy.4.
    
    If this proxy is not dated, it will be deemed to bear the date on which it is mailed by
Management to the holder.5.
    
    The securities represented by this proxy will be voted as directed by the holder, however, if
such a direction is not made in respect of any matter, this proxy will be voted as recommended
by Management.6.
    
    The securities represented by this proxy will be voted or withheld from voting, in accordance
with the instructions of the holder, on any ballot that may be called for and, if the holder
has specified a choice with respect to any matter to be acted on, the securities will be voted
accordingly.7.
    
    This proxy confers discretionary authority in respect of amendments to matters identified in
the notice of meeting or other matters that may properly come before the meeting.  VOTE USING THE TELEPHONE OR INTERNET 24 HOURS A DAY 7 DAYS A WEEK! Voting by mail
 Voting by mail or by Internet
  (VOTE USING THE TELEPHONE)  
    
    Call the toll free number listed BELOW from a touch tone telephone. There is NO CHARGEfor this call.1 8XX XXX-XXXX
    
    Proxy Instructions must be received by 5:00 pm, Eastern Time, February 17, 2005.
  (VOTE USING THE INTERNET)  
    
    Go to the following web site:www.computershare.com/ca/proxy
    
    Proxy Instructions must be received by 5:00 pm, Eastern Time, February 17, 2005.
 
   To vote by telephone or the Internet, you will need to provide your HOLDER ACCOUNT NUMBER and
ACCESS NUMBER listed below. HOLDER ACCOUNT NUMBER  C1234567890          ACCESS NUMBER  12345 If you vote by telephone or the Internet, DO NOT mail back this proxy.  006DZB




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(SAMPLE GRAPHICS) Appointment of ProxyholderI/We being holder(s) of the Corporation hereby appoint:
Peter A. Crossgrove, Chairman, or failing him, Howard Beck.
    
    OR
    
    Print the name of the person you are
appointing if this person is someone
other than the Chairman of the Meeting.
 as my/our proxyholder with full power of substitution and to vote in accordance with the following direction (or if no directions have been given, as the proxyholder sees fit) and all other
matters that may properly come before the Special Meeting of MASONITE
INTERNATIONAL CORPORATION to be held at Sheraton Centre Toronto Hotel, Essex Ballroom & Foyer, 123
Queen Street West, Toronto, Ontario on February 18, 2005 at 9:30 am and at any adjournment thereof. Resolution Management recommends a vote FOR the following resolution. Please read the resolution in full in the accompanying Management Information Circular. For
    
    Against
    
    Abstain1
    
    A special resolution (the Arrangement Resolution) approving the arrangement of Masonite
under section 182 of the Business Corporations Act (Ontario).
    
    4
    
    o
    
    o
    
    oThe full text of the Arrangement
Resolution is set out on Appendix A to the Management
Information Circular dated January 18, 2005 (the Circular) with respect to the Meeting,
as such Arrangement Resolution may be amended or varied at the Meeting.
  _____
Fold  Authorized Signature(s)  Sign Here  This section must be completed for your instructions to be executed. If no voting instructions are
indicated above, this Proxy will be voted as recommended by Management.
 Signature(s) Day
    (MOLQ GRAPHICS)