SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                          ----------------------------

                                    FORM 8-K


                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                          ----------------------------

Date of Report (Date of earliest event reported): April 5, 2001

                        Millennium Pharmaceuticals, Inc.
---------------------------------------------------------------------------
             (Exact name of Registrant as Specified in its Charter)


      Delaware                   0-28494                  04-3177038
----------------------------   --------------        ----------------------
(State or Other Jurisdiction    (Commission             (IRS Employer
     of Incorporation)          File Number)            Identification No.)



                75 Sidney Street, Cambridge, Massachusetts         02139
---------------------------------------------------------------------------
         (Address of Principal Executive Offices)                (Zip Code)


Registrant's telephone number, including area code:  (617) 679-7000
                                                     --------------



                                 Not Applicable
---------------------------------------------------------------------------
          (Former Name or Former Address if Changed Since Last Report)




<PAGE>


ITEM 5:  OTHER EVENTS.

On April 5, 2001, the Board of Directors of Millennium Pharmaceuticals, Inc.
(the "Company"), declared a dividend of one Right for each outstanding share of
the Company's Common Stock to stockholders of record at the close of business on
April 16, 2001 (the "Record Date"). Each Right entitles the registered holder to
purchase from the Company one one-thousandth of a share of Series A Junior
Participating Preferred Stock, $.001 par value per share (the "Preferred
Stock"), at a Purchase Price of $200 in cash, subject to adjustment. The
description and terms of the Rights are set forth in a Rights Agreement dated
April 5, 2001 (the "Rights Agreement") between the Company and State Street Bank
and Trust Company, N.A., as Rights Agent, a copy of which is filed as an exhibit
to this Current Report on Form 8-K.

Initially, the Rights are not exercisable and will be attached to all
certificates representing outstanding shares of Common Stock, and no separate
Rights Certificates will be distributed. The Rights will separate from the
Common Stock, and the Distribution Date will occur, upon the earlier of (i) 10
business days following the first date of a public announcement that a person or
group of affiliated or associated persons (an "Acquiring Person") has acquired,
or obtained the right to acquire, beneficial ownership of 15% or more of the
outstanding shares of Common Stock (the "Stock Acquisition Date"), or (ii) 10
business days following the commencement of a tender offer or exchange offer
that would result in a person or group beneficially owning 15% or more of the
outstanding shares of Common Stock. The Distribution Date may be deferred in
circumstances determined by the Board of Directors. In addition, certain
inadvertent acquisitions will not trigger the occurrence of the Distribution
Date. Until the Distribution Date (or earlier redemption or expiration of the
Rights), (i) the Rights will be evidenced by the Common Stock certificates
outstanding on the Record Date, together with a Summary of Rights to be mailed
to stockholders, or by new Common Stock certificates issued after the Record
Date which contain a notation incorporating the Rights Agreement by reference,
(ii) the Rights will be transferred with and only with such Common Stock
certificates; and (iii) the surrender for transfer of any certificates for
Common Stock outstanding (with or without a copy of the Summary of Rights or
such notation) will also constitute the transfer of the Rights associated with
the Common Stock represented by such certificate.

The Rights are not exercisable until the Distribution Date and will expire upon
the close of business on April 5, 2011 (the "Final Expiration Date") unless
earlier redeemed or exchanged as described below. As soon as practicable after
the Distribution Date, separate Rights Certificates will be mailed to holders of
record of the Common Stock as of the close of business on the Distribution Date
and, thereafter, the separate Rights Certificates alone will represent the
Rights. Except as otherwise determined by the Board of Directors, and except for
shares of Common Stock issued upon exercise, conversion or exchange of then
outstanding options, convertible or exchangeable securities or other contingent
obligations to issue shares or pursuant to any employee benefit plan or
arrangement, only shares of Common Stock issued prior to the Distribution Date
will be issued with Rights.

In the event that any Person becomes an Acquiring Person, unless the event
causing the 15% threshold to be crossed is a Permitted Offer (as defined in the
Rights Agreement),



                                       2
<PAGE>


then, promptly following the first occurrence of such event, each holder of a
Right (except as provided below and in Section 7(e) of the Rights Agreement)
shall thereafter have the right to receive, upon exercise, that number of shares
of Common Stock of the Company (or, in certain circumstances, cash, property or
other securities of the Company) which equals the exercise price of the Right
divided by 50% of the current market price (as defined in the Rights Agreement)
per share of Common Stock at the date of the occurrence of such event. However,
Rights are not exercisable following such event until such time as the Rights
are no longer redeemable by the Company as described below. Notwithstanding any
of the foregoing, following the occurrence of such event, all Rights that are,
or (under certain circumstances specified in the Rights Agreement) were,
beneficially owned by any Acquiring Person will be null and void. The event
summarized in this paragraph is referred to as a "Section 11(a)(ii) Event."

For example, at an exercise price of $200 per Right, each Right not owned by an
Acquiring Person (or by certain related parties) following a Section 11(a)(ii)
Event would entitle its holder to purchase for $200 such number of shares of
Common Stock (or other consideration, as noted above) as equals $200 divided by
one-half of the current market price (as defined in the Rights Agreement) of the
Common Stock. Assuming that the Common Stock had a market price of $50 per share
at such time, the holder of each valid Right would be entitled to purchase eight
shares of Common Stock, having a market value of 8 x $50, or $400, for $200.

In the event that, at any time after any Person becomes an Acquiring Person, (i)
the Company is consolidated with, or merged with and into, another entity and
the Company is not the surviving entity of such consolidation or merger (other
than a consolidation or merger which follows a Permitted Offer) or if the
Company is the surviving entity, but shares of its outstanding Common Stock are
changed or exchanged for stock or securities (of any other person) or cash or
any other property, or (ii) more than 50% of the Company's assets or earning
power is sold or transferred, each holder of a Right (except Rights which
previously have been voided as set forth above) shall thereafter have the right
to receive, upon exercise, that number of shares of common stock of the
acquiring company which equals the exercise price of the Right divided by 50% of
the current market price (as defined in the Rights Agreement) of such common
stock at the date of the occurrence of the event. The events summarized in this
paragraph are referred to as "Section 13 Events." A Section 11(a)(ii) Event and
Section 13 Events are collectively referred to as "Triggering Events."

For example, at an exercise price of $200 per Right, each valid Right following
a Section 13 Event would entitle its holder to purchase for $200 such number of
shares of common stock of the acquiring company as equals $200 divided by
one-half of the current market price (as defined in the Rights Agreement) of
such common stock. Assuming that such common stock had a market price of $50 per
share at such time, the holder of each valid Right would be entitled to purchase
eight shares of common stock of the acquiring company, having a market value of
8 x $50, or $400, for $200.

At any time after the occurrence of a Section 11(a)(ii) Event, when no person
owns a majority of the Common Stock, the Board of Directors of the Company may
exchange the



                                       3
<PAGE>


Rights (other than Rights owned by such Acquiring Person which have become
void), in whole or in part, at an exchange ratio of one share of Common Stock,
or one one-thousandth of a share of Preferred Stock (or of a share of a class or
series of the Company's preferred stock having equivalent rights, preferences
and privileges), per Right (subject to adjustment).

The Purchase Price payable, and the number of units of Preferred Stock or other
securities or property issuable, upon exercise of the Rights are subject to
adjustment from time to time to prevent dilution (i) in the event of a stock
dividend on, or a subdivision, combination or reclassification of, the Preferred
Stock, (ii) if holders of the Preferred Stock are granted certain rights or
warrants to subscribe for Preferred Stock or convertible securities at less than
the then-current market price (as defined in the Rights Agreement) of the
Preferred Stock, or (iii) upon the distribution to holders of the Preferred
Stock of evidences of indebtedness or assets (excluding regular periodic cash
dividends paid out of earnings or retained earnings) or of subscription rights
or warrants (other than those referred to above). The number of Rights
associated with each share of Common Stock is also subject to adjustment in the
event of a stock split of the Common Stock or a stock dividend on the Common
Stock payable in Common Stock or subdivisions, consolidations or combinations of
the Common Stock occurring, in any such case, prior to the Distribution Date.

With certain exceptions, no adjustment in the Purchase Price will be required
until cumulative adjustments amount to at least 1% of the Purchase Price. No
fractional shares of Preferred Stock (other than fractions which are integral
multiples of one one-thousandth of a share of Preferred Stock) will be issued
and, in lieu thereof, an adjustment in cash will be made based on the market
price of the Preferred Stock on the last trading date prior to the date of
exercise.

Preferred Stock purchasable upon exercise of the Rights will not be redeemable.
Each share of Preferred Stock will be entitled to receive, when, as and if
declared by the Board of Directors, a minimum preferential quarterly dividend
payment of $10 per share or, if greater, an aggregate dividend of 1000 times the
dividend declared per share of Common Stock. In the event of liquidation, the
holders of the Preferred Stock will be entitled to a minimum preferential
liquidation payment of $1000 per share, plus an amount equal to accrued and
unpaid dividends, and will be entitled to an aggregate payment of 1000 times the
payment made per share of Common Stock. Each share of Preferred Stock will have
1000 votes, voting together with the Common Stock. In the event of any merger,
consolidation or other transaction in which Common Stock is changed or
exchanged, each share of Preferred Stock will be entitled to receive 1000 times
the amount received per share of Common Stock. These rights are protected by
customary antidilution provisions. Because of the nature of the Preferred
Stock's dividend, liquidation and voting rights, the value of one one-thousandth
of a share of Preferred Stock purchasable upon exercise of each Right should
approximate the value of one share of Common Stock.

At any time prior to the earlier of the tenth Business Day (or such later date
as may be determined by the Board of Directors of the Company) after the Stock
Acquisition Date, the Company may redeem the Rights in whole, but not in part,
at a price of $.001 per Right



                                       4
<PAGE>


(the "Redemption Price"), payable in cash or stock. Immediately upon the
redemption of the Rights or such earlier time as established by the Board in the
resolution ordering the redemption of the Rights, the Rights will terminate and
the only right of the holders of Rights will be to receive the Redemption Price.
The Rights may also be redeemable following certain other circumstances
specified in the Rights Agreement.

Until a Right is exercised, the holder thereof, as such, will have no rights as
a stockholder of the Company, including, without limitation, the right to vote
or to receive dividends. Although the distribution of the Rights should not be
taxable to stockholders or to the Company, stockholders may, depending upon the
circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of the acquiring company as set forth above.

Any provision of the Rights Agreement, other than the redemption price, may be
amended by the Board prior to such time as the Rights are no longer redeemable.
Once the Rights are no longer redeemable, the Board's authority to amend the
Rights is limited to correcting ambiguities or defective or inconsistent
provisions in a manner that does not adversely affect the interest of holders of
Rights.

The Rights are intended to protect the stockholders of the Company in the event
of an unfair or coercive offer to acquire the Company and to provide the Board
with adequate time to evaluate unsolicited offers. The Rights may have
anti-takeover effects. The Rights will cause substantial dilution to a person or
group that attempts to acquire the Company without conditioning the offer on a
substantial number of Rights being acquired. The Rights, however, should not
affect any prospective offeror willing to make an offer at a fair price and
otherwise in the best interests of the Company and its stockholders, as
determined by a majority of the Board. The Rights should not interfere with any
merger or other business combination approved by the Board.

This summary description of the Rights does not purport to be complete and is
qualified in its entirety by reference to the Rights Agreement and the exhibits
thereto which is attached hereto as an Exhibit and is incorporated herein by
reference.

ITEM 7:  FINANCIAL STATEMENTS PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

         (c)  Exhibits.

              4.1     Rights Agreement dated April 5, 2001 by and between
                      Millennium Pharmaceuticals, Inc. and State Street Bank and
                      Trust Company, N.A. which includes as Exhibit A the Form
                      of Certificate of Designations of Series A Junior
                      Participating Preferred Stock, as Exhibit B the Form of
                      Rights Certificate and as Exhibit C the Summary of Rights
                      to Purchase Common Stock.


                                       5
<PAGE>


                                   SIGNATURES

Pursuant to the requirements of the Securities Act of 1934, the Registrant has
duly caused this report to be signed on its behalf by the undersigned hereunto
duly authorized.





                                               MILLENNIUM PHARMACEUTICALS, INC.



Date:  April 5, 2001                           /s/ JOHN B. DOUGLAS III
                                               John B. Douglas III
                                               Senior Vice President and
                                               General Counsel

                                       6
<PAGE>


                                  EXHIBIT INDEX



EXHIBIT NUMBER                           DESCRIPTION
--------------                           -----------

4.1                                      Rights Agreement dated April 5, 2001 by
                                         and between Millennium Pharmaceuticals,
                                         Inc. and State Street Bank and Trust
                                         Company, N.A. which includes as Exhibit
                                         A the Form of Certificate of
                                         Designations of Series A Junior
                                         Participating Preferred Stock, as
                                         Exhibit B the Form of Rights
                                         Certificate and as Exhibit C the
                                         Summary of Rights to Purchase Common
                                         Stock.



                                       7
<PAGE>
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{"company-data": {"conformed-name": "MILLENNIUM PHARMACEUTICALS INC", "cik": "0001002637", "assigned-sic": "2834", "irs-number": "043177038", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-28494", "film-number": "1596263"}, "business-address": {"street1": "75 SIDNEY STREET", "city": "CAMBRIDGE", "state": "MA", "zip": "02139", "phone": "6176797000"}, "mail-address": {"street1": "640 MEMORIAL DR", "city": "CAMBRIDGE", "state": "MA", "zip": "02139"}}
SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                          ----------------------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                          ----------------------------

Date of Report (Date of earliest event reported): April 5, 2001

                        Millennium Pharmaceuticals, Inc.
---------------------------------------------------------------------------
             (Exact name of Registrant as Specified in its Charter)

      Delaware                   0-28494                  04-3177038
----------------------------   --------------        ----------------------
(State or Other Jurisdiction    (Commission             (IRS Employer
     of Incorporation)          File Number)            Identification No.)

                75 Sidney Street, Cambridge, Massachusetts         02139
---------------------------------------------------------------------------
         (Address of Principal Executive Offices)                (Zip Code)

Registrant's telephone number, including area code:  (617) 679-7000
                                                     --------------

                                 Not Applicable
---------------------------------------------------------------------------
          (Former Name or Former Address if Changed Since Last Report)
ITEM 5:  OTHER EVENTS.

On April 5, 2001, the Board of Directors of Millennium Pharmaceuticals, Inc.
(the "Company"), declared a dividend of one Right for each outstanding share of
the Company's Common Stock to stockholders of record at the close of business on
April 16, 2001 (the "Record Date"). Each Right entitles the registered holder to
purchase from the Company one one-thousandth of a share of Series A Junior
Participating Preferred Stock, $.001 par value per share (the "Preferred
Stock"), at a Purchase Price of $200 in cash, subject to adjustment. The
description and terms of the Rights are set forth in a Rights Agreement dated
April 5, 2001 (the "Rights Agreement") between the Company and State Street Bank
and Trust Company, N.A., as Rights Agent, a copy of which is filed as an exhibit
to this Current Report on Form 8-K.

Initially, the Rights are not exercisable and will be attached to all
certificates representing outstanding shares of Common Stock, and no separate
Rights Certificates will be distributed. The Rights will separate from the
Common Stock, and the Distribution Date will occur, upon the earlier of (i) 10
business days following the first date of a public announcement that a person or
group of affiliated or associated persons (an "Acquiring Person") has acquired,
or obtained the right to acquire, beneficial ownership of 15% or more of the
outstanding shares of Common Stock (the "Stock Acquisition Date"), or (ii) 10
business days following the commencement of a tender offer or exchange offer
that would result in a person or group beneficially owning 15% or more of the
outstanding shares of Common Stock. The Distribution Date may be deferred in
circumstances determined by the Board of Directors. In addition, certain
inadvertent acquisitions will not trigger the occurrence of the Distribution
Date. Until the Distribution Date (or earlier redemption or expiration of the
Rights), (i) the Rights will be evidenced by the Common Stock certificates
outstanding on the Record Date, together with a Summary of Rights to be mailed
to stockholders, or by new Common Stock certificates issued after the Record
Date which contain a notation incorporating the Rights Agreement by reference,
(ii) the Rights will be transferred with and only with such Common Stock
certificates; and (iii) the surrender for transfer of any certificates for
Common Stock outstanding (with or without a copy of the Summary of Rights or
such notation) will also constitute the transfer of the Rights associated with
the Common Stock represented by such certificate.

The Rights are not exercisable until the Distribution Date and will expire upon
the close of business on April 5, 2011 (the "Final Expiration Date") unless
earlier redeemed or exchanged as described below. As soon as practicable after
the Distribution Date, separate Rights Certificates will be mailed to holders of
record of the Common Stock as of the close of business on the Distribution Date
and, thereafter, the separate Rights Certificates alone will represent the
Rights. Except as otherwise determined by the Board of Directors, and except for
shares of Common Stock issued upon exercise, conversion or exchange of then
outstanding options, convertible or exchangeable securities or other contingent
obligations to issue shares or pursuant to any employee benefit plan or
arrangement, only shares of Common Stock issued prior to the Distribution Date
will be issued with Rights.

In the event that any Person becomes an Acquiring Person, unless the event
causing the 15% threshold to be crossed is a Permitted Offer (as defined in the
Rights Agreement),

                                       2
then, promptly following the first occurrence of such event, each holder of a
Right (except as provided below and in Section 7(e) of the Rights Agreement)
shall thereafter have the right to receive, upon exercise, that number of shares
of Common Stock of the Company (or, in certain circumstances, cash, property or
other securities of the Company) which equals the exercise price of the Right
divided by 50% of the current market price (as defined in the Rights Agreement)
per share of Common Stock at the date of the occurrence of such event. However,
Rights are not exercisable following such event until such time as the Rights
are no longer redeemable by the Company as described below. Notwithstanding any
of the foregoing, following the occurrence of such event, all Rights that are,
or (under certain circumstances specified in the Rights Agreement) were,
beneficially owned by any Acquiring Person will be null and void. The event
summarized in this paragraph is referred to as a "Section 11(a)(ii) Event."

For example, at an exercise price of $200 per Right, each Right not owned by an
Acquiring Person (or by certain related parties) following a Section 11(a)(ii)
Event would entitle its holder to purchase for $200 such number of shares of
Common Stock (or other consideration, as noted above) as equals $200 divided by
one-half of the current market price (as defined in the Rights Agreement) of the
Common Stock. Assuming that the Common Stock had a market price of $50 per share
at such time, the holder of each valid Right would be entitled to purchase eight
shares of Common Stock, having a market value of 8 x $50, or $400, for $200.

In the event that, at any time after any Person becomes an Acquiring Person, (i)
the Company is consolidated with, or merged with and into, another entity and
the Company is not the surviving entity of such consolidation or merger (other
than a consolidation or merger which follows a Permitted Offer) or if the
Company is the surviving entity, but shares of its outstanding Common Stock are
changed or exchanged for stock or securities (of any other person) or cash or
any other property, or (ii) more than 50% of the Company's assets or earning
power is sold or transferred, each holder of a Right (except Rights which
previously have been voided as set forth above) shall thereafter have the right
to receive, upon exercise, that number of shares of common stock of the
acquiring company which equals the exercise price of the Right divided by 50% of
the current market price (as defined in the Rights Agreement) of such common
stock at the date of the occurrence of the event. The events summarized in this
paragraph are referred to as "Section 13 Events." A Section 11(a)(ii) Event and
Section 13 Events are collectively referred to as "Triggering Events."

For example, at an exercise price of $200 per Right, each valid Right following
a Section 13 Event would entitle its holder to purchase for $200 such number of
shares of common stock of the acquiring company as equals $200 divided by
one-half of the current market price (as defined in the Rights Agreement) of
such common stock. Assuming that such common stock had a market price of $50 per
share at such time, the holder of each valid Right would be entitled to purchase
eight shares of common stock of the acquiring company, having a market value of
8 x $50, or $400, for $200.

At any time after the occurrence of a Section 11(a)(ii) Event, when no person
owns a majority of the Common Stock, the Board of Directors of the Company may
exchange the

                                       3
Rights (other than Rights owned by such Acquiring Person which have become
void), in whole or in part, at an exchange ratio of one share of Common Stock,
or one one-thousandth of a share of Preferred Stock (or of a share of a class or
series of the Company's preferred stock having equivalent rights, preferences
and privileges), per Right (subject to adjustment).

The Purchase Price payable, and the number of units of Preferred Stock or other
securities or property issuable, upon exercise of the Rights are subject to
adjustment from time to time to prevent dilution (i) in the event of a stock
dividend on, or a subdivision, combination or reclassification of, the Preferred
Stock, (ii) if holders of the Preferred Stock are granted certain rights or
warrants to subscribe for Preferred Stock or convertible securities at less than
the then-current market price (as defined in the Rights Agreement) of the
Preferred Stock, or (iii) upon the distribution to holders of the Preferred
Stock of evidences of indebtedness or assets (excluding regular periodic cash
dividends paid out of earnings or retained earnings) or of subscription rights
or warrants (other than those referred to above). The number of Rights
associated with each share of Common Stock is also subject to adjustment in the
event of a stock split of the Common Stock or a stock dividend on the Common
Stock payable in Common Stock or subdivisions, consolidations or combinations of
the Common Stock occurring, in any such case, prior to the Distribution Date.

With certain exceptions, no adjustment in the Purchase Price will be required
until cumulative adjustments amount to at least 1% of the Purchase Price. No
fractional shares of Preferred Stock (other than fractions which are integral
multiples of one one-thousandth of a share of Preferred Stock) will be issued
and, in lieu thereof, an adjustment in cash will be made based on the market
price of the Preferred Stock on the last trading date prior to the date of
exercise.

Preferred Stock purchasable upon exercise of the Rights will not be redeemable.
Each share of Preferred Stock will be entitled to receive, when, as and if
declared by the Board of Directors, a minimum preferential quarterly dividend
payment of $10 per share or, if greater, an aggregate dividend of 1000 times the
dividend declared per share of Common Stock. In the event of liquidation, the
holders of the Preferred Stock will be entitled to a minimum preferential
liquidation payment of $1000 per share, plus an amount equal to accrued and
unpaid dividends, and will be entitled to an aggregate payment of 1000 times the
payment made per share of Common Stock. Each share of Preferred Stock will have
1000 votes, voting together with the Common Stock. In the event of any merger,
consolidation or other transaction in which Common Stock is changed or
exchanged, each share of Preferred Stock will be entitled to receive 1000 times
the amount received per share of Common Stock. These rights are protected by
customary antidilution provisions. Because of the nature of the Preferred
Stock's dividend, liquidation and voting rights, the value of one one-thousandth
of a share of Preferred Stock purchasable upon exercise of each Right should
approximate the value of one share of Common Stock.

At any time prior to the earlier of the tenth Business Day (or such later date
as may be determined by the Board of Directors of the Company) after the Stock
Acquisition Date, the Company may redeem the Rights in whole, but not in part,
at a price of $.001 per Right

                                       4
(the "Redemption Price"), payable in cash or stock. Immediately upon the
redemption of the Rights or such earlier time as established by the Board in the
resolution ordering the redemption of the Rights, the Rights will terminate and
the only right of the holders of Rights will be to receive the Redemption Price.
The Rights may also be redeemable following certain other circumstances
specified in the Rights Agreement.

Until a Right is exercised, the holder thereof, as such, will have no rights as
a stockholder of the Company, including, without limitation, the right to vote
or to receive dividends. Although the distribution of the Rights should not be
taxable to stockholders or to the Company, stockholders may, depending upon the
circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of the acquiring company as set forth above.

Any provision of the Rights Agreement, other than the redemption price, may be
amended by the Board prior to such time as the Rights are no longer redeemable.
Once the Rights are no longer redeemable, the Board's authority to amend the
Rights is limited to correcting ambiguities or defective or inconsistent
provisions in a manner that does not adversely affect the interest of holders of
Rights.

The Rights are intended to protect the stockholders of the Company in the event
of an unfair or coercive offer to acquire the Company and to provide the Board
with adequate time to evaluate unsolicited offers. The Rights may have
anti-takeover effects. The Rights will cause substantial dilution to a person or
group that attempts to acquire the Company without conditioning the offer on a
substantial number of Rights being acquired. The Rights, however, should not
affect any prospective offeror willing to make an offer at a fair price and
otherwise in the best interests of the Company and its stockholders, as
determined by a majority of the Board. The Rights should not interfere with any
merger or other business combination approved by the Board.

This summary description of the Rights does not purport to be complete and is
qualified in its entirety by reference to the Rights Agreement and the exhibits
thereto which is attached hereto as an Exhibit and is incorporated herein by
reference.

ITEM 7:  FINANCIAL STATEMENTS PRO FORMA FINANCIAL INFORMATION AND EXHIBITS.

         (c)  Exhibits.

              4.1     Rights Agreement dated April 5, 2001 by and between
                      Millennium Pharmaceuticals, Inc. and State Street Bank and
                      Trust Company, N.A. which includes as Exhibit A the Form
                      of Certificate of Designations of Series A Junior
                      Participating Preferred Stock, as Exhibit B the Form of
                      Rights Certificate and as Exhibit C the Summary of Rights
                      to Purchase Common Stock.

                                       5
SIGNATURES

Pursuant to the requirements of the Securities Act of 1934, the Registrant has
duly caused this report to be signed on its behalf by the undersigned hereunto
duly authorized.

                                               MILLENNIUM PHARMACEUTICALS, INC.

Date:  April 5, 2001                           /s/ JOHN B. DOUGLAS III
                                               John B. Douglas III
                                               Senior Vice President and
                                               General Counsel

                                       6
EXHIBIT INDEX

EXHIBIT NUMBER                           DESCRIPTION
--------------                           -----------

4.1                                      Rights Agreement dated April 5, 2001 by
                                         and between Millennium Pharmaceuticals,
                                         Inc. and State Street Bank and Trust
                                         Company, N.A. which includes as Exhibit
                                         A the Form of Certificate of
                                         Designations of Series A Junior
                                         Participating Preferred Stock, as
                                         Exhibit B the Form of Rights
                                         Certificate and as Exhibit C the
                                         Summary of Rights to Purchase Common
                                         Stock.

                                       7