As filed with the Securities and Exchange Commission on September 15, 2004
                                           REGISTRATION STATEMENT NO. 333-100122
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                           --------------------------

                        POST-EFFECTIVE AMENDMENT NO. 1 TO
                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                           --------------------------

                              MOLDFLOW CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

              DELAWARE                                  04-3406763
      (STATE OF INCORPORATION)             (I.R.S. EMPLOYER IDENTIFICATION NO.)

                              430 BOSTON POST ROAD
                          WAYLAND, MASSACHUSETTS 01778
                                 (508) 358-5848
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)

            MOLDFLOW CORPORATION 2000 STOCK OPTION AND INCENTIVE PLAN
                            (FULL TITLE OF THE PLAN)

                                A. ROLAND THOMAS
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                              MOLDFLOW CORPORATION
                              430 BOSTON POST ROAD
                          WAYLAND, MASSACHUSETTS 01778
                                 (508) 358-5848
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)

                           --------------------------

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                          DEREGISTRATION OF SECURITIES

      Moldflow Corporation, a Delaware corporation (the "Registrant"), filed a
Registration Statement on Form S-8 (File No. 333-100122) (the "Registration
Statement") with the Securities and Exchange Commission (the "Commission") on
September 26, 2002, registering 10,282 shares of the Registrant's Common Stock,
$.01 par value per share (the "Common Stock"), authorized for issuance under the
Registrant's 2000 Stock Option and Incentive Plan (the "Plan"). At the time of
the initial filing of the Registration Statement, 2,928 shares were registered
in error. The Registrant hereby files this Post-Effective Amendment No. 1 to the
Registration Statement on Form S-8 in order to remove from registration the
2,928 shares registered in error therefore decreasing the total number of shares
registered under the Registration Statement to 7,354 shares from 10,282 shares.
Since no securities are being registered in connection with this post-effective
amendment, no additional registration fee is being paid.

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                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 1. Incorporation of Documents by Reference.


      Pursuant to General Instruction E to Form S-8, Moldflow Corporation (the
"Registrant") hereby incorporates by reference the contents of its Registration
Statement on Form S-8 filed with the Securities and Exchange Commission (the
"Commission") on September 20, 2000 under file number 333-46162.

                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Post-Effective
Amendment No. 1 to the Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the Town of Wayland, Commonwealth of
Massachusetts, on this 15th day of September, 2004.

                         MOLDFLOW CORPORATION



                         By: /s/ Suzanne E. MacCormack
                            ---------------------------------------

                            Suzanne E. MacCormack

                            Executive Vice President and Chief Financial Officer

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      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.



         SIGNATURE                              TITLE                              DATE
         ---------                              -----                              ----
                                                                     
                              President and Chief Executive Officer and    September 15, 2004
/s/ A. Roland Thomas           Director (Principal Executive Officer)
- --------------------------
A. Roland Thomas

                            Executive Vice President and Chief Financial   September 15, 2004
                              Officer (Principal Financial Officer and
/s/ Suzanne E. MacCormack           Principal Accounting Officer)
- --------------------------
Suzanne E. MacCormack


           *                     Chairman of the Board of Directors        September 15, 2004
- --------------------------
Marc J.L. Dulude


           *                                  Director                     September 15, 2004
- --------------------------
Roger E. Brooks


           *                                  Director                     September 15, 2004
- --------------------------
Frank W. Haydu III


                                              Director
- --------------------------
Robert J. Lepofsky


           *                                  Director                     September 15, 2004
- --------------------------
Robert P. Schechter

* By:  /s/ Suzanne E. MacCormack
       -----------------------------
       Suzanne E. MacCormack
       (Attorney-in-fact)


                                  EXHIBIT INDEX

Exhibit No.       Description
- -----------       -----------

5.1               Opinion of Goodwin Procter LLP as to the legality of the
                  securities being registered.

23.1              Consent of Counsel (included in Exhibit 5.1 hereto).

23.2              Consent of PricewaterhouseCoopers LLP.

24.1*             Powers of Attorney.

* Previously filed.