EXHIBIT 10.4

As amended through September 26, 2005 and
adjusted for stock splits in April and October 2000


                        MILLENNIUM PHARMACEUTICALS, INC.

                        1996 EMPLOYEE STOCK PURCHASE PLAN


         The purpose of this Plan is to provide eligible employees of Millennium
Pharmaceuticals, Inc. (the "Company") and certain of its subsidiaries with
opportunities to purchase shares of the Company's Common Stock (the "Common
Stock"). Five Million Six Hundred Thousand (5,600,000) shares of Common Stock in
the aggregate have been approved for this purpose.

         1. ADMINISTRATION. The Plan will be administered by the Company's Board
 of Directors (the "Board") or by a Committee appointed by the Board (the
 "Committee"). The Board or the Committee has authority to make rules and
 regulations for the administration of the Plan and its interpretation and
 decisions with regard thereto shall be final and conclusive.

         2. ELIGIBILITY. Participation in the Plan will neither be permitted nor
denied contrary to the requirements of Section 423 of the Internal Revenue Code
of 1986, as amended (the "Code"), and regulations promulgated thereunder. All
individuals designated, classified or otherwise considered by the Company, or
by any subsidiary of the Company (as defined in Section 424(f) of the Code)
designated by the Board or the Committee from time to time (a "Designated
Subsidiary"), to be employees, including directors who are employees, are
eligible to participate in any one or more of the offerings of Options (as
defined below) to purchase Common Stock under the Plan, provided that:

              (a) they are regularly employed by the Company or a Designated
Subsidiary for more than 20 hours a week and for more than five months in a
calendar year; and

              (b) they are employees of the Company or a Designated
Subsidiary on the first day of the applicable Plan Period (as defined below).

         No employee may be granted an option hereunder if such employee,
immediately after the option is granted, owns 5% or more of the total combined
voting power or value of the stock of the Company or any subsidiary. For
purposes of the preceding sentence, the attribution rules of Section 424(d) of
the Code shall apply in determining the stock ownership of an employee, and all
stock which the employee has a contractual right to purchase shall be treated as
stock owned by the employee.

         3. OFFERINGS. The Company will make one or more offerings ("Offerings")
to employees to purchase Common Stock under this Plan. The Board or the
Committee shall determine the commencement dates of each of the Offerings (the
"Offering Commencement Dates"). Each Offering Commencement Date will begin a
period (a "Plan Period") during which payroll deductions will be made and held
for the purchase of Common Stock at the end of the Plan Period. The Board or the
Committee shall choose a Plan Period of twelve (12) months or less for each of
the Offerings and may, at its discretion, choose a different Plan Period for
each Offering.

         4. PARTICIPATION. An employee eligible on the Offering Commencement
Date of any Offering may participate in such Offering by complying with the
directions set forth and completing the materials required by the Company or the
Company's outside administrator of this Plan. By participating the employee will
authorize a regular payroll deduction from the Compensation received by the
employee during the Plan Period. Unless an employee changes her election as
provided herein or withdraws from the Plan, her deductions and purchases will
continue at the same rate for future Offerings under the Plan as long as the
Plan remains in effect. The term "Compensation" means the amount of money
reportable on the employee's Federal Income Tax Withholding Statement, excluding
overtime, shift premium, incentive or bonus awards, allowances and
reimbursements for expenses such as relocation allowances for travel expenses,
income or gains on the exercise of Company stock options or stock appreciation
rights, and similar items, whether or not shown on the employee's Federal Income
Tax Withholding Statement, but including, in the case of salespersons, sales
commissions to the extent determined by the Board or the Committee.

         5. DEDUCTIONS.

              (a) The Company will maintain payroll deduction accounts for
all participating employees. With respect to any Offering made under this Plan,
an employee may authorize a payroll deduction in any dollar amount up to a
maximum of 10% of the Compensation he or she receives during the Plan Period or
such shorter period during which deductions from payroll are made. Payroll
deductions may be at the rate of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of
Compensation.

              (b) No employee may be granted an Option which permits his
rights to purchase Common Stock under this Plan and any other stock purchase
plan of the Company and its subsidiaries, to accrue at a rate which exceeds
$25,000 of the fair market value of such Common Stock (determined at the
Offering Commencement Date of the Plan Period) for each calendar year in which
the Option is outstanding at any time.

         6. DEDUCTION CHANGES. An employee may decrease or discontinue her
payroll deduction once during any Plan Period by following the instructions
provided by the Company or the Company's outside administrator of this Plan. An
employee may only effect such decrease or discontinuation for a particular Plan
Period prior to the beginning of the enrollment period for the subsequent Plan
Period as such enrollment period is designated by the Board, the Committee or
the Committee's authorized designee or such other time as is so designated. An
employee may not increase her payroll deduction during a Plan Period. If an
employee elects to discontinue her payroll deductions during a Plan Period, but
does not elect to withdraw her funds pursuant to Section 8 hereof, funds
deducted prior to her election to discontinue will be applied to the purchase of
Common Stock on the Exercise Date (as defined below).

         7. INTEREST. Interest will not be paid on any employee payroll
deduction accounts, except to the extent that the Board or its Committee, in its
sole discretion, elects to credit such accounts with interest at such per annum
rate as it may from time to time determine.

         8. WITHDRAWAL OF FUNDS. An employee may on any one occasion during a
Plan Period and for any reason withdraw all of the balance accumulated in the
employee's payroll deduction account. Any such withdrawal for a particular Plan
Period must be effected prior to the beginning of the enrollment period for the
subsequent Plan Period as such enrollment period is designated by the Board, the
Committee or the Committee's authorized designee or such other time as is so
designated. If the employee makes such a withdrawal, the employee shall thereby
withdraw from participation in the Offering and may not begin participation
again during the remainder of the Plan Period. Any employee withdrawing such
balance may participate in any subsequent Offering in accordance with terms and
conditions established by the Board or the Committee and subject to currently
applicable law.

         9. PURCHASE OF SHARES.

              (a) On the Offering Commencement Date of each Plan Period, the
Company will grant to each eligible employee who is then a participant in the
Plan an option (an "Option") to purchase on the last business day of such Plan
Period (the "Exercise Date"), at the Option Price hereinafter provided for, such
number of whole shares of Common Stock of the Company reserved for the purposes
of the Plan as does not exceed the number of shares determined by dividing 15%
of such employee's annualized Compensation for the immediately prior six-month
period by the price determined in accordance with the formula set forth in the
following paragraph but using the closing price on the Offering Commencement
Date of such Plan Period.

              (b) The Option Price for each share purchased will be 85% of
the closing price of the Common Stock on (i) the first business day of such Plan
Period or (ii) the Exercise Date, whichever closing price shall be less. Such
closing price shall be (A) the closing price of the Common Stock on any national
securities exchange on which the Common Stock is listed, or (B) the closing
price of the Common Stock on the Nasdaq National Market ("Nasdaq") or (C) the
average of the closing bid and asked prices in the over-the-counter market,
whichever is applicable, as published in THE WALL STREET JOURNAL. If no sales of
Common Stock were made on such a day, the price of the Common Stock for purposes
of clauses (A) and (B) above shall be the reported price for the next preceding
day on which sales were made.

              (c) Each employee who continues to be a participant in the
Plan on the Exercise Date shall be deemed to have exercised his Option at the
Option Price on such date and shall be deemed to have purchased from the Company
the number of full shares of Common Stock reserved for the purpose of the Plan
that his accumulated payroll deductions on such date will pay for pursuant to
the formula set forth above (but not in excess of the maximum number determined
in the manner set forth above).

              (d) Any balance remaining in an employee's payroll deduction
account at the end of a Plan Period will be automatically refunded to the
employee, except that any balance which is less than the purchase price of one
share of Common Stock will be carried forward into the employee's payroll
deduction account for the following Offering, unless the employee elects not to
participate in the following Offering under the Plan, in which case the balance
in the employee's account shall be refunded.

         10. ISSUANCE OF CERTIFICATES. Certificates representing shares of
Common Stock purchased under the Plan may be issued only in the name of the
employee, in the name of the employee and another person of legal age as joint
tenants with rights of survivorship, or (in the Company's sole discretion) in
the street name of a brokerage firm, bank or other nominee holder designated by
the employee.

         11. RIGHTS ON RETIREMENT, DEATH OR TERMINATION OF EMPLOYMENT. In the
event of a participating employee's termination of employment prior to the last
business day of a Plan Period (whether as a result of the employee's voluntary
or involuntary termination, retirement, death or otherwise), no payroll
deduction shall be taken from any pay due and owing to the employee and the
balance in the employee's payroll deduction account shall be paid to the
employee or, in the event of the employee's death, (a) to a beneficiary
previously designated in a revocable notice signed by the employee (with any
spousal consent required under state law) or (b) in the absence of such a
designated beneficiary, to the executor or administrator of the employee's
estate or (c) if no such executor or administrator has been appointed to the
knowledge of the Company, to such other person(s) as the Company may, in its
discretion, designate. If, prior to the last business day of the Plan Period,
the Designated Subsidiary by which an employee is employed shall cease to be a
subsidiary of the Company, or if the employee is transferred to a subsidiary of
the Company that is not a Designated Subsidiary, the employee shall be deemed to
have terminated employment for the purposes of this Plan.

         12. OPTIONEES NOT STOCKHOLDERS. Neither the granting of an Option to an
employee nor the deductions from his pay shall constitute such employee a
stockholder of the shares of Common Stock covered by an Option under this Plan
until such shares have been purchased by and issued to him.

         13. RIGHTS NOT TRANSFERABLE. Rights under this Plan are not
transferable by a participating employee other than by will or the laws of
descent and distribution, and are exercisable during the employee's lifetime
only by the employee.

         14. APPLICATION OF FUNDS. All funds received or held by the Company
under this Plan may be combined with other corporate funds and may be used for
any corporate purpose.

         15. ADJUSTMENT IN CASE OF CHANGES AFFECTING COMMON STOCK. In the event
of a subdivision of outstanding shares of Common Stock, or the payment of a
dividend in Common Stock, the number of shares approved for this Plan, and the
share limitation set forth in Section 9, shall be increased proportionately, and
such other adjustment shall be made as may be deemed equitable by the Board or
the Committee. In the event of any other change affecting the Common Stock, such
adjustment shall be made as may be deemed equitable by the Board or the
Committee to give proper effect to such event.

         16. MERGER.

              (a) If the Company shall at any time merge or consolidate with
another corporation and the holders of the capital stock of the Company
immediately prior to such merger or consolidation continue to hold at least 80%
by voting power of the capital stock of the surviving corporation ("Continuity
of Control"), the holder of each Option then outstanding will thereafter be
entitled to receive at the next Exercise Date upon the exercise of such Option
for each share as to which such Option shall be exercised the securities or
property which a holder of one share of the Common Stock was entitled to upon
and at the time of such merger, and the Board or the Committee shall take such
steps in connection with such merger as the Board or the Committee shall deem
necessary to assure that the provisions of Section 15 shall thereafter be
applicable, as nearly as reasonably may be, in relation to the said securities
or property as to which such holder of such Option might thereafter be entitled
to receive thereunder.

              (b) In the event of a merger or consolidation of the Company
with or into another corporation which does not involve Continuity of Control,
or of a sale of all or substantially all of the assets of the Company while
unexercised Options remain outstanding under the Plan, (i) subject to the
provisions of clauses (ii) and (iii), after the effective date of such
transaction, each holder of an outstanding Option shall be entitled, upon
exercise of such Option, to receive in lieu of shares of Common Stock, shares of
such stock or other securities as the holders of shares of Common Stock received
pursuant to the terms of such transaction; or (ii) all outstanding Options may
be cancelled by the Board or the Committee as of a date prior to the effective
date of any such transaction and all payroll deductions shall be paid out to the
participating employees; or (iii) all outstanding Options may be cancelled by
the Board or the Committee as of the effective date of any such transaction,
provided that notice of such cancellation shall be given to each holder of an
Option, and each holder of an Option shall have the right to exercise such
Option in full based on payroll deductions then credited to his account as of a
date determined by the Board or the Committee, which date shall not be less than
ten (10) days preceding the effective date of such transaction.

         17. AMENDMENT OF THE PLAN. The Board may at any time, and from time to
time, amend this Plan in any respect, except that (a) if the approval of any
such amendment by the stockholders of the Company is required by Section 423 of
the Code or by Rule 16b-3 under the Exchange Act, such amendment shall not be
effected without such approval, and (b) in no event may any amendment be made
which would cause the Plan to fail to comply with Section 16 of the Exchange Act
and the rules promulgated thereunder, as in effect from time to time, or Section
423 of the Code.

         18. INSUFFICIENT SHARES. In the event that the total number of shares
of Common Stock specified in elections to be purchased under any Offering plus
the number of shares purchased under previous Offerings under this Plan exceeds
the maximum number of shares issuable under this Plan, the Board or the
Committee will allot the shares then available on a pro rata basis.

         19. TERMINATION OF THE PLAN. This Plan may be terminated at any time by
the Board. Upon termination of this Plan all amounts in the payroll deduction
accounts of participating employees shall be promptly refunded.

         20. GOVERNMENTAL REGULATIONS.

              (a) The Company's obligation to sell and deliver Common Stock
under this Plan is subject to listing on a national stock exchange or quotation
on Nasdaq and the approval of all governmental authorities required in
connection with the authorization, issuance or sale of such stock.

              (b) The Plan shall be governed by the laws of the State of
Delaware except to the extent that such law is preempted by federal law.

              (c) The Plan is intended to comply with the provisions of Rule
16b-3 promulgated under the Exchange Act. Any provision inconsistent with such
Rule shall to that extent be inoperative and shall not affect the validity of
the Plan.

         21. ISSUANCE OF SHARES. Shares may be issued upon exercise of an Option
from authorized but unissued Common Stock, from shares held in the treasury of
the Company, or from any other proper source.

         22. NOTIFICATION UPON SALE OF SHARES. Each employee agrees, by entering
the Plan, to promptly give the Company notice of any disposition of shares
purchased under the Plan where such disposition occurs within two years after
the date of grant of the Option pursuant to which such shares were purchased.

         23. EFFECTIVE DATE AND APPROVAL OF STOCKHOLDERS. The Plan shall take
effect upon the closing of the Company's initial public offering of Common Stock
pursuant to an effective registration statement under the Securities Act of
1933, as amended, subject to approval by the stockholders of the Company as
required by Rule 16b-3 under the Exchange Act and by Section 423 of the Code,
which approval must occur within twelve months of the adoption of the Plan by
the Board.