EXHIBIT 3.3

                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                       OF

                             BROOKS AUTOMATION, INC.

      Brooks Automation, Inc., a corporation organized and existing under the
laws of the State of Delaware (the "Corporation"), pursuant to Section 242 of
the Delaware General Corporation Law, DOES HEREBY CERTIFY:

      FIRST: That, the Board of Directors of the Corporation, by unanimous
written consent dated January 6, 2000, in accordance with the provisions of
Section 141(f) of the General Corporation Law of the State of Delaware, duly
adopted a resolution setting forth a proposed amendment to the Corporation's
Certificate of Incorporation. The resolution setting forth the proposed
amendment is as follows:

      RESOLVED:   To amend, subject to the approval by the stockholders of the
                  Corporation, the Corporation's Certificate of Incorporation to
                  increase the number of shares of the Corporation's common
                  stock authorized thereunder from 21,500,000 to 43,000,000 and
                  to submit the amendment to the Corporation's Certificate of
                  Incorporation to the stockholders of the Corporation for their
                  consideration, with a recommendation for approval of the
                  amendment.

      SECOND:     The foregoing amendment to the Certificate of Incorporation
                  was duly adopted by the stockholders at a meeting duly held,
                  at which a quorum was present and acting throughout and in
                  accordance with the provisions of Section 242 of the General
                  Corporation Law of Delaware, on February 24, 2000.

      THIRD:      That the Certificate of Incorporation be amended by Deleting
                  the first paragraph of Article Fourth in its entirety and
                  replacing it as follows:

                  "The total number of shares of all classes of stock which the
                  Corporation shall have authority to issue is (i) 43,000,000
                  shares of Common Stock, $.01 par value per share (the "Common
                  Stock"), and (ii) 1,000,000 shares of Preferred Stock, $.01
                  par value per share (the "Preferred Stock")."

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      IN WITNESS WHEREOF, the Corporation has caused this certificate to be
signed by Robert J. Therrien, President, and attested to by Samuel P. Williams,
Assistant Secretary, as of this 4th day of May, 2000.

                                                     BROOKS AUTOMATION, INC.

                                                     By: /s/ Robert J. Therrien
                                                         ----------------------
                                                         Robert J. Therrien
                                                         President

ATTEST:

By: /s/ Samuel P. Williams
    -------------------------
    Samuel P. Williams
    Assistant Secretary