<PAGE>

                                                                Exhibit 10.5

                   AMENDMENT TO REGISTRATION RIGHTS AGREEMENT


     This Amendment to Registration Rights Agreement (the "Amendment") is made
and entered into as of February 16, 2001 by and among Breakaway Solutions, Inc.,
a Delaware corporation (the "Company"), ICG Holdings, Inc., a Delaware
corporation ("ICG"), and SCP Private Equity Partners II, L.P., a Delaware
limited partnership ("SCP").

                                   BACKGROUND


     The Company and ICG are parties to a Registration Rights Agreement dated as
of January 19, 2001 (the "Agreement"). Pursuant to a Loan and Security Agreement
dated as of the date hereof (the "SCP Loan Agreement"), among Company, SCP as
lender and SCP, as agent, SCP will lend Ten Million Dollars ($10,000,000) to
Company. As an inducement for SCP to enter into the SCP Loan Agreement, the
Company desires to amend the Agreement as set forth herein. The capitalized
terms used in this Amendment shall have the respective meanings specified in the
Agreement unless otherwise herein defined or the context shall otherwise
require.

     Now, therefore, in consideration of the promises hereinafter contained, and
each intending to be legally bound hereby, the parties agree as follows:

     1. JOINDER OF SCP. Each of the Company and ICG hereby agrees that SCP shall
be deemed to be a party to the Agreement and shall have the rights and
obligations accorded thereunder. SCP hereby agrees to be bound by all of the
terms and conditions of the Agreement, as if SCP was an original party thereto.

     2. AMENDMENT OF SECTION 1. Section 1 of the Agreement is hereby amended in
its entirety to read as follows:

     "1. DEFINITIONS. All capitalized terms used but not otherwise defined
herein shall have the meanings ascribed to them in the SCP Loan Agreement and
the Loan and Security Agreement, dated as of January 19, 2001, as amended, among
the Company, ICG and SCP, as agent."

     3. MISCELLANEOUS.

          (a) The Agreement, as amended hereby, shall be binding upon and shall
inure to the benefit of the Company, ICG and SCP and their respective successors
and assigns.

          (b) This Amendment shall be construed in connection with and as part
of the Agreement, and all terms, conditions and covenants contained in the
Agreement, except as herein modified, shall remain in full force and effect.

          (c) This Amendment may be executed in two or more counterparts
     (including by means of telecopied signature pages), all of which shall be
     considered one and the same agreement.

                                      2

<PAGE>



          IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
     of the date first above written.

                             SCP PRIVATE EQUITY PARTNERS II, L.P.
                             BY:  SCP Private Equity II General Partner, L.P.,
                                  its General Partner
                             BY:  SCP Private Equity II, LLC


                             By: /s/ Wayne B. Weisman
                                -----------------------------------
                             Name:  Wayne B. Weisman
                             Title: Manager


                             ICG HOLDINGS, INC.


                             By: /s/ Henry N. Nassau
                                -----------------------------------
                             Name:  Henry N. Nassau
                             Title: Vice President and Secretary



                             BREAKAWAY SOLUTIONS, INC.


                             By: /s/ Gordon Brooks
                                -----------------------------------
                             Name:  Gordon Brooks
                             Title: President and Chief Executive Officer