POWER OF ATTORNEY

The undersigned hereby constitutes and appoints each of Aaron C. von
Staats and Christopher J. MacKrell, signing singly, the undersigned's
true and lawful attorney-in-fact to:

(1) execute for and on behalf of the undersigned, in the undersigned
capacity as an officer and/or director of Parametric Technology
Corporation (the "Company"), Forms 3, 4 and 5 in accordance with Section
16(a) of the Securities Exchange Act of 1934 and the rules thereunder;

(2) do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such Form
3, 4 or 5, complete and execute any amendment or amendments thereto, and
timely file such form with the United States Securities and Exchange
Commission and any stock exchange or similar authority; and

(3) take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit
to, in the best interest of, or legally required by, the undersigned, it
being understood that the documents executed by such attorney-in-fact on
behalf of the undersigned pursuant to this Power of Attorney shall be in
such form and shall contain such terms and conditions as such attorney-in-fact
may approve in such attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and
powers herein granted, as fully to all intents and purposes as the undersigned
might or could do if personally present, with full power of substitution or
revocation, hereby ratifying and confirming all that such attorney-in-fact,
or such attorney-in-fact's substitute or substitutes, shall lawfully do or
cause to be done by virtue of this power of attorney and the rights and powers
herein granted.  The undersigned acknowledges that the foregoing
attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4 and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the
Company, unless earlier revoked by the undersigned in a signed writing
delivered to the foregoing attorneys-in-fact.




IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 3rd day of February, 2003.

/s/ Noel G. Posternak
Signature

Noel G. Posternak
Print Name