EXHIBIT NO. 99.4(jj)

                                  AMENDMENT #1
                                  TO INVESTMENT
                               ADVISORY AGREEMENT

AMENDMENT dated as of September 1, 2005 to the Investment Advisory Agreement
dated August 31, 2000, as amended, by and between MFS/Sun Life Series Trust (the
"Trust") on behalf of the Mid Cap Growth Series (a "Fund") and Massachusetts
Financial Services Company, a Delaware corporation (the "Adviser") (the
"Agreement").

                                   WITNESSETH

WHEREAS, the Trust on behalf of each Fund has entered into the Agreement with
the Adviser; and

WHEREAS, the Adviser has agreed to amend the Agreement as provided below;

NOW THEREFORE, in consideration of the mutual covenants and agreements of the
parties hereto as herein set forth, the parties covenant and agree as follows:

         1. Amendment of the Agreement: Article 3. Compensation of the Adviser
is deleted in its entirety and replaced with the following:

            ARTICLE 3. COMPENSATION OF THE ADVISER. For the services to be
            rendered and the facilities provided, the Fund shall pay to the
            Adviser an investment advisory fee computed and paid annually at a
            rate equal to 0.75% on the first $1 billion of the Fund's average
            daily net assets and 0.70% on assets in excess of $1 billion of the
            Fund's average daily net assets. If the Adviser shall serve for
            less than the whole of any period specified in this Article 3, the
            compensation to the Adviser will be prorated.

         2. Miscellaneous: Except as set forth in this Amendment, the Agreement
shall remain in full force and effect, without amendment or modification.

         3. Limitation of Liability of the Trustees and Shareholders: A copy of
the Trust's Declaration of Trust is on file with the Secretary of State of The
Commonwealth of Massachusetts. The parties hereto acknowledge that the
obligations of or arising out of this instrument are not binding upon any of the
Trust's trustees, officers, employees, agents or shareholders individually, but
are binding solely upon the assets and property of the Trust in accordance with
its proportionate interest hereunder. If this instrument is executed by the
Trust on behalf of one or more series of the Trust, the parties hereto
acknowledge that the assets and liabilities of each series of the Trust are
separate and distinct and that the obligations of or arising out of this
instrument are binding solely upon the assets or property of the series on whose
behalf the Trust has executed this instrument. If the Trust has executed this
instrument on behalf of more than one series of the Trust, the parties hereto
also agree that the obligations of each series hereunder shall be several and
not joint, in accordance with its proportionate interest hereunder, and the
parties hereto agree not to proceed against any series for the obligations of
another series.

IN WITNESS WHEREOF, the parties have caused this Amendment to the Agreement to
be executed and delivered in the names and on their behalf by the undersigned,
therewith duly authorized, all as of the day and year first above written.



                                   MFS/SUN LIFE SERIES TRUST
                                   on behalf of Mid Cap Growth Series

                                   By: SUSAN S. NEWTON
                                       -------------------------------
                                        Susan S. Newton
                                        Assistant Secretary



                                   MASSACHUSETTS FINANCIAL SERVICES COMPANY

                                   By: JEFFREY N. CARP
                                       -------------------------------
                                        Jeffrey N. Carp
                                        Executive Vice President