EXHIBIT 99.1

                      AMENDMENT NO. 1 TO RIGHTS AGREEMENT

         This Amendment No. 1 (this "Amendment"), dated as of August 3, 2006, is
by and between MRO Software, Inc. (formerly known as Project Software &
Development, Inc.), a Massachusetts corporation (the "Company"), and American
Stock Transfer & Trust Company, as the successor to BankBoston, N.A. (the
"Rights Agent").

         WHEREAS, the Company and the Rights Agent are parties to the Rights
Agreement, dated as of January 27, 1998 (the "Rights Agreement");

         WHEREAS, capitalized terms used but not otherwise defined in this
Amendment shall have the meaning given them in the Rights Agreement;

         WHEREAS, the board of directors of the Company has adopted a certain
Agreement and Plan of Merger (the "Merger Agreement") by and among the Company,
International Business Machines Corp., a New York corporation ("IBM"), and
Kennesaw Acquisition Corporation, a Massachusetts corporation wholly owned by
IBM ("IBM Merger Sub") (IBM and IBM Merger Sub are collectively referred to
herein as the "Other Parties") at a meeting of the board of directors of the
Company held on August 3, 2006 (the "Meeting"), pursuant to which IBM Merger Sub
will be merged with and into the Company (the "Merger");

         WHEREAS, upon the effectiveness of the Merger, the Other Parties
collectively will acquire more than 15% of the outstanding shares of the
Company's Common Stock, $.01 par value per share (the "Company's Common Stock");

         WHEREAS, the acquisition of more than 15% of the outstanding shares of
the Company's Common Stock would result in the acquiring entity or entities
being deemed to be an "Acquiring Person" under the Rights Agreement, which would
trigger certain events pursuant to the terms of the Rights Agreement;

         WHEREAS, at the Meeting the board of directors of the Company
determined that it is in the best interest of the Company to amend the Rights
Agreement prior to the Company entering into the Merger Agreement so that (i)
the Other Parties will not thereby become Acquiring Persons under the Rights
Agreement, (ii) neither a Distribution Date nor a Stock Acquisition Date will
thereby occur, and (iii) the Expiration Date of the Agreement will be
immediately prior to the Effective Time, as defined in the Merger Agreement;

         WHEREAS, pursuant to Section 26 of the Rights Agreement, this Amendment
is being executed by the Company and the Rights Agent for the purpose of
amending the Rights Agreement as set forth below.

         NOW THEREFORE, in consideration of the mutual covenants and conditions
contained herein, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:


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         1.       Section 1(a) of the Rights Agreement (definition of "Acquiring
Person") is hereby amended by addition thereto of the following final sentence:

                  Notwithstanding anything in this Agreement to the contrary,
                  the term "Acquiring Person" shall not include either
                  International Business Machines Corp., a New York corporation
                  ("IBM"), or Kennesaw Acquisition Sub, Inc., a Massachusetts
                  corporation wholly owned by IBM ("IBM Merger Sub"), or any
                  other subsidiary of IBM (IBM, IBM Merger Sub, and any other
                  subsidiary of IBM are collectively referred to herein as the
                  "Other Parties"), solely by reason of the execution, delivery
                  or performance of the Agreement and Plan of Merger authorized
                  and approved by the Board of Directors of the Company at the
                  meeting of the Board of Directors held on August 3, 2006, as
                  it may be amended from time to time (the "Merger Agreement"),
                  the consummation of the Merger (as defined in the Merger
                  Agreement) or the other transactions contemplated by the
                  Merger Agreement or compliance with the terms of the Merger
                  Agreement, including proxies or agreements to vote Common
                  Shares of the Company granted by the Company or any
                  stockholder of the Company to the Other Parties in connection
                  with the Merger Agreement.

         2.       Section 1(u) of the Rights Agreement (definition of "Final
Expiration Date") is hereby deleted and replace in its entirety with the
following:

                  (u) "Final Expiration Date" shall mean the earlier of (i)
                  Close of Business on January 27, 2008, and (ii) immediately
                  prior to the Effective Time (as defined in the Merger
                  Agreement).

         3.       Section 1(kk) of the Rights Agreement (definition of "Stock
Acquisition Date") is hereby amended to add the following sentence at the end
thereof:

                  Notwithstanding anything in this Agreement to the contrary, a
                  Stock Acquisition Date shall not occur solely by reason of the
                  execution, delivery or performance of the Merger Agreement,
                  the consummation of the Merger or the other transactions
                  contemplated by the Merger Agreement or compliance with the
                  terms of the Merger Agreement, including proxies or agreements
                  to vote Common Shares of the Company granted by the Company or
                  any stockholder of the Company to the Other Parties in
                  connection with the Merger Agreement.

         4.       Section 3(b) of the Rights Agreement is hereby amended to add
the following sentence at the end thereof:

                  Notwithstanding anything in this Agreement to the contrary, a
                  Distribution Date shall not occur solely by reason of the
                  execution, delivery or performance of the Merger Agreement,
                  the consummation of the Merger or the other transactions
                  contemplated by the Merger Agreement or compliance with the
                  terms of the Merger Agreement, including proxies or agreements
                  to vote Common Shares of


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                  the Company granted by the Company or any stockholder of the
                  Company to the Other Parties in connection with the Merger
                  Agreement.

         5.       Section 7(a) of the Rights Agreement is hereby amended to add
the following sentence at the end thereof:

                  Notwithstanding anything in this Agreement to the contrary, no
                  Right shall become exercisable in accordance with this
                  Agreement solely by reason of the execution, delivery or
                  performance of the Merger Agreement, the consummation of the
                  Merger or the other transactions contemplated by the Merger
                  Agreement or compliance with the terms of the Merger
                  Agreement, including proxies or agreements to vote Common
                  Shares of the Company granted by the Company or any
                  stockholder of the Company to the Other Parties in connection
                  with the Merger Agreement.

         6.       Section 21 of the Rights Agreement is hereby amended to delete
the phrase "at least $100,000,000" stated therein and replace it with the phrase
"at least $25,000,000".

         7.       Except as specifically amended by this Amendment, the Rights
Agreement shall remain in full force and effect.


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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 1
to be duly executed as of the date first above written.

                              MRO SOFTWARE, INC.


                              By:  /s/ Norman E. Drapeau, Jr.
                                   --------------------------------------------
                                   Name:  Norman E. Drapeau, Jr.
                                   Title: President and Chief Executive Officer

                              American Stock Transfer & Trust Company

                              By:  /s/  Herbert J. Lemmer
                                   --------------------------------------------
                                   Name:  Herbert J. Lemmer
                                   Title: Vice President


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