EXHIBIT 10.1


May 25, 2006

Anna Protopapas
Millennium Pharmaceuticals, Inc.
40 Landsdowne Street
Cambridge, MA 02139

Dear Anna:

This letter documents the agreement between you and Millennium Pharmaceuticals,
Inc. ("Millennium" or the "Company"), made in consideration of continued
employment by you and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, concerning the terms of a
severance payment payable to you under certain conditions as described below.

1.   In the event that your employment is terminated by Millennium other than
     for Justifiable Cause (as defined below), Millennium will pay you a
     severance payment (the "Severance Payment") equal to twelve (12) months'
     base salary, at your then current rate of pay. The Severance Payment will
     be payable periodically in accordance with Millennium's payroll procedures
     as then in effect, commencing with the first payroll period following
     termination of employment. In the event your employment is terminated by
     Millennium for Justifiable Cause or voluntarily by you, you will not be
     entitled to any Severance Payment.

2.   "Justifiable Cause" shall mean the occurrence of any of the following
     events:  (i) your conviction of, or plea of nolo contendere with respect to
     a felony or a crime involving moral turpitude, (ii) your commission of an
     act of personal dishonesty or breach of fiduciary duty involving personal
     profit in connection with the Company, (iii) your commission of an act, or
     failure to act, which the Board of Directors of the Company shall
     reasonably have found to have involved willful misconduct or gross
     negligence on your part, in the conduct of your duties as an employee of
     the Company, (iv) habitual absenteeism, alcoholism or drug dependence on
     your part which interferes with the performance of your duties as an
     employee of the Company, (v) your willful and material failure or refusal
     to perform your services as an employee of the Company, (vi) any material
     breach by you to fulfill the terms and conditions under which you are
     employed by the Company, or (viii) your willful and material failure or
     refusal to carry out a direct request of the Board of Directors or Chief
     Executive Officer.  In the event that Millennium terminates your employment
     for Justifiable Cause, Millennium will provide you with a statement of the
     basis for such termination and an opportunity to respond thereto.

3.   The payment to you of the amounts payable under Paragraph 1 shall be
     conditioned upon the execution by you of a release in the form provided by
     the Company and shall constitute your sole remedy in the event of your
     termination of employment in the circumstances set forth in Paragraph 1.

4.   This agreement may be amended or modified only by a written instrument
     executed by you and Millennium. This agreement will be interpreted and
     enforced in accordance with the laws of the Commonwealth of Massachusetts.

5.   Any notice delivered under this agreement shall be deemed duly delivered
     when personally delivered, or four business days after it is sent by
     registered or certified mail, return receipt requested, postage prepaid, or
     one business day after it is sent for next-business day delivery via a
     reputable nationwide overnight courier service to the Company at 40
     Landsdowne Street, Cambridge, MA 02139, Attn: Vice President of Human
     Resources, or to you at your address as listed above. Either party may
     change the address to which notices are to be delivered by giving notice of
     such change to the other party in the manner set forth in this paragraph.

6.   This agreement constitutes the entire agreement between the parties with
     respect to the subject matters hereof, and supersedes all prior agreements
     and understandings, whether written or oral, with respect to such subject
     matters.

7.   This agreement shall be binding upon and inure to the benefit of both
     parties and their respective successors and assigns, including any
     corporation with which, or into which, the Company may be merged, or which
     may succeed to the Company's assets or business, provided, however, that
     your obligations to the Company are personal and shall not be assigned.

Please acknowledge your agreement by countersigning this letter below.

                                    Sincerely,

                                    MILLENNIUM PHARMACEUTICALS, INC.

                                    By: /S/ DEBORAH DUNSIRE
                                        Deborah Dunsire
                                        Chief Executive Officer
AGREED TO:

/S/ ANNA PROTOPAPAS
Anna Protopapas

Dated: MAY 25, 2006