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                                                                    EXHIBIT 10.1

                          MOMENTA PHARMACEUTICALS, INC.

                            2002 STOCK INCENTIVE PLAN

               (AMENDED AND RESTATED PLAN AS OF DECEMBER 18, 2002)


     1. PURPOSE. The purpose of this plan (the "Plan") is to secure for Momenta
Pharmaceuticals, a Delaware corporation (the "Company"), and its shareholders
the benefits arising from capital stock ownership by employees, officers and
directors of, and consultants or advisors to, the Company and its parent and
subsidiary corporations who are expected to contribute to the Company's future
growth and success. Under the Plan recipients may be awarded both (i) Options
(as defined in Section 2.1) to purchase the Company's common stock, par value
$.0001 per share ("Common Stock") and (ii) shares of the Company's Common Stock
("Restricted Stock Awards"). Except where the context otherwise requires, the
term "Company" shall include the parent and all present and future subsidiaries
of the Company as defined in Sections 424(e) and 424(f) of the Internal Revenue
Code of 1986, as amended or replaced from time to time (the "Code"). Those
provisions of the Plan which make express reference to Section 422 shall apply
only to Incentive Stock Options (as that term is defined in the Plan).

     2. TYPES OF AWARDS AND ADMINISTRATION.

         2.1 OPTIONS. Options granted pursuant to the Plan ("Options")
shall be authorized by action of the Board of Directors of the Company and may
be either incentive stock options ("Incentive Stock Options") meeting the
requirements of Section 422 of the Code or non-statutory Options which are not
intended to meet the requirements of Section 422 of the Code. All Options when
granted are intended to be non-statutory Options, unless the applicable Option
Agreement (as defined in Section 5.1) explicitly states that the Option is
intended to be an Incentive Stock Option. If an Option is intended to be an
Incentive Stock Option, and if for any reason such Option (or any portion
thereof) shall not qualify as an Incentive Stock Option, then, to the extent of
such nonqualification, such Option (or portion thereof) shall be regarded as a
non-statutory Option appropriately granted under the Plan provided that such
Option (or portion thereof) otherwise meets the Plan's requirements relating to
non-statutory Options. The vesting of Options may be conditioned upon the
completion of a specified period of employment with the Company and/or such
other conditions or events as the Board may determine. The Board may also
provide that Options are immediately exercisable subject to certain repurchase
rights in the Company dependent upon the continued employment of the optionee
and/or such other conditions or event as the Board may determine.

         2.2 RESTRICTED STOCK AWARDS. The Board in its discretion may
grant Restricted Stock Awards, entitling the recipient to acquire, for a
purchase price determined by the Board, shares of Common Stock subject to such
restrictions and conditions as the Board may determine at the time of grant
("Restricted Stock"), including continued employment and/or achievement of
pre-established performance goals and objectives.

         2.3 ADMINISTRATION. The Plan shall be administered by the Board
of Directors of the Company, whose construction and interpretation of the terms
and provisions of the Plan shall be final and conclusive. The Board of Directors
may in its sole discretion issue Restricted Stock

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and grant Options to purchase shares of Common Stock, and issue shares upon
exercise of such Options as provided in the Plan. The Board shall have
authority, subject to the express provisions of the Plan, to construe the
respective Restricted Stock Agreements (as defined in Section 5.2), Option
Agreements and the Plan, to prescribe, amend and rescind rules and regulations
relating to the Plan, to determine the terms and provisions of the respective
Restricted Stock Agreements and Option Agreements, and to make all other
determinations in the judgment of the Board of Directors necessary or desirable
for the administration of the Plan. The Board of Directors may correct any
defect or supply any omission or reconcile any inconsistency in the Plan or in
any Restricted Stock Agreement or Option Agreement in the manner and to the
extent it shall deem expedient to carry the Plan into effect and it shall be the
sole and final judge of such expediency. No director or person acting pursuant
to authority delegated by the Board of Directors shall be liable for any action
or determination under the Plan made in good faith. The Board of Directors may,
to the full extent permitted by or consistent with applicable laws or
regulations (including, without limitation, applicable state law), delegate any
or all of its powers under the Plan to a committee (the "Committee") appointed
by the Board of Directors, and if the Committee is so appointed all references
to the Board of Directors in the Plan shall mean and relate to such Committee.

     3. ELIGIBILITY. Options may be granted, and Restricted Stock may be issued,
to persons who are, at the time of such grant or issuance, employees, officers
or directors of, or consultants or advisors to, the Company; PROVIDED, that the
class of persons to whom Incentive Stock Options may be granted shall be limited
to employees of the Company.

     4. STOCK SUBJECT TO PLAN. Subject to adjustment as provided in Section 14
below, the maximum number of shares of Common Stock of the Company which may be
issued under the Plan is 1,028,662 shares. If an Option shall expire or
terminate for any reason without having been exercised in full, the unpurchased
shares subject to such Option shall again be available for subsequent Option
grants under the Plan. If shares of Restricted Stock shall be forfeited to, or
otherwise repurchased by, the Company pursuant to a Restricted Stock Agreement,
such purchased shares shall again be available for subsequent Option grants or
Restricted Stock Awards under the Plan. If shares issued upon exercise of an
Option are tendered to the Company in payment of the exercise price of an
Option, such tendered shares shall again be available for subsequent Option
grants under the Plan.

     5. FORMS OF RESTRICTED STOCK AGREEMENTS AND OPTION AGREEMENTS.

         5.1 OPTION AGREEMENT. As a condition to the grant of an Option, each
recipient of an Option shall execute an option agreement ("Option Agreement") in
such form not inconsistent with the Plan as may be approved by the Board of
Directors. Such Option Agreements may differ among recipients.

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         5.2 RESTRICTED STOCK AGREEMENT. As a condition to the issuance of
Restricted Stock, each recipient thereof shall execute an agreement ("Restricted
Stock Agreement") in such form not inconsistent with the Plan as may be approved
by the Board of Directors. Such Restricted Stock Agreements may differ among
recipients and need not be entitled "Restricted Stock Agreements."

         5.3 "STAND-OFF" AGREEMENT. Unless the Board of Directors specifies
otherwise, each Restricted Stock Agreement and each Option Agreement shall
provide that the holder of any Option or the purchaser of any Restricted Stock
agrees (i) for a period of 180 days from the effective date of any registration
of securities of the Company in connection with an underwritten public offering
under the Securities Act of 1933, as amended (the "Securities Act"), not to
sell, make any short sale of, loan, grant any option for the purchase of, or
otherwise dispose of any shares of the Company's common stock owned or
controlled by him (other than those shares permitted to be included in the
offering), without the prior written consent of the Company or the underwriters
managing such offering, and (ii) to execute any agreement reflecting clause (i)
above as may be requested by the Company or the managing underwriters at the
time of such offering.

         5.4 RIGHT OF FIRST REFUSAL. Unless the Board of Directors specifies
otherwise, each Restricted Stock Agreement and each Option Agreement shall
provide that the Company shall have a right of first refusal with respect to the
transfer or proposed transfer of any Restricted Stock (whether or not subject to
vesting limitations) or shares issued upon exercise of any Option granted
hereunder.

     6. PURCHASE PRICE.

         6.1 GENERAL. The purchase price per share of Restricted Stock and per
share of stock deliverable upon the exercise of an Option shall be determined by
the Board of Directors, PROVIDED, HOWEVER, that in the case of an Incentive
Stock Option, the exercise price shall not be less than 100% of the fair market
value of such stock, as determined by the Board of Directors, at the time of
grant of such Option, or less than 110% of such fair market value in the case of
Options described in Section 11.2.

         6.2 PAYMENT OF PURCHASE PRICE. Option Agreements may provide for the
payment of the exercise price by delivery of cash or a check to the order of the
Company in an amount equal to the exercise price of such Options, or, to the
extent provided in the applicable Option Agreement, (i) by delivery to the
Company of shares of Common Stock of the Company already owned by the optionee
for a period of six months and having a fair market value equal in amount to the
exercise price of the Options being exercised, (ii) a personal recourse note
issued by the optionee to the Company in a principal amount equal to such
aggregate exercise price and with such other terms, including interest rate and
maturity, as the Company may determine in its discretion; PROVIDED, HOWEVER,
that the interest rate borne by such note shall not be less than the lowest
applicable federal rate, as defined in Section 1274(d) of the Code, (iii) by any
other means which the Board of Directors determines are consistent with the
purpose of the Plan and with applicable laws and regulations or (iv) by any
combination of such methods of payment. The fair market value of any shares of
the Company's Common Stock or other non-cash

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consideration which may be delivered upon exercise of an Option shall be
determined by the Board of Directors. Restricted Stock Agreements may provide
for the payment of any purchase price in any manner approved by the Board of
Directors at the time of authorizing the issuance thereof.

     7. OPTION PERIOD. Each Option and all rights thereunder shall expire on
such date as shall be set forth in the applicable Option Agreement, PROVIDED
THAT, in any event, in the case of an Incentive Stock Option, such date shall
not be later than 10 years after the date on which the Option is granted (or
five years in the case of Options described in Section 11.2), and, in the case
of non-statutory Options, not later than 10 years after the date on which the
Option is granted, and, in either case, shall be subject to earlier termination
as provided in the Plan.

     8. EXERCISE OF OPTIONS. Each Option shall be exercisable either in full or
in installments at such time or times and during such period as shall be set
forth in the agreement evidencing such Option, subject to the provisions of the
Plan.

     9. NONTRANSFERABILITY OF OPTIONS. No Option shall be assignable or
transferable by the person to whom it is granted, either voluntarily or by
operation of law, except by will or the laws of descent and distribution. During
the life an optionee, an Option held by him or her shall be exercisable only by
the optionee.

     10. EFFECT OF TERMINATION. No Incentive Stock Option may be exercised
unless, at the time of such exercise, the optionee is, and has continuously
since the date of grant of his or her Incentive Stock Option been, employed by
the Company, except that, unless the Option Agreement or instrument expressly
provides otherwise:

         10.1 the Incentive Stock Option may be exercised within the period of
thirty days (or within such lesser period as may be specified in the applicable
Option Agreement) after the date the optionee's employment with the Company
terminates other than for death, disability or termination for Cause;

         10.2 if the optionee dies while in the employ of the Company, the
Incentive Stock Option may be exercised by the person to whom it is transferred
by will or the laws of descent and distribution within the period of one hundred
and eighty days after the date of death (or within such lesser period as may be
specified in the applicable Option Agreement);

         10.3 if the optionee becomes disabled (within the meaning of Section
22(e)(3) of the Code or any successor provision thereto) while in the employ of
the Company, the Incentive Stock Option may be exercised within the period of
one hundred and eighty days after the date the optionee ceases to be such an
employee because of such disability (or within such lesser period as may be
specified in the applicable Option Agreement); and

         10.4 if the optionee's employment with the Company is terminated by the
Company for Cause, the Incentive Stock Option shall terminate immediately. The
term "Cause" shall mean (a) any breach by the optionee of any agreement to which
the optionee and the Company are both parties (including, without limitation,
breach by the optionee of any provision of any employment, consulting, advisory,
nondisclosure, non-competition or other similar agreement), (b) any act (other
than retirement) or omission to act by the optionee which may have a material

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and adverse effect on the Company's business or on the optionee's ability to
perform services for the Company, including, without limitation, the commission
of any crime (other than minor traffic violations), or (c) any material
misconduct or material neglect of duties by the optionee in connection with the
business or affairs of the Company or any parent, subsidiary or affiliate of the
Company. The optionee shall be considered to have been discharged for Cause if
the Company determines, within 30 days after the optionee's resignation, that
discharge for Cause was warranted. The Board shall have sole authority and
discretion to determine whether the optionee's employment has been terminated
for Cause;

PROVIDED, HOWEVER, that in no event may any Incentive Stock Option be exercised
after the expiration date of the Incentive Stock Option. For all purposes of the
Plan and any Incentive Stock Option granted hereunder, "employment" shall be
defined in accordance with the provisions of Section 1.421-7(h) of the Income
Tax Regulations (or any successor regulations).

     A non-statutory Option granted to an employee shall be subject to the
foregoing provisions of this Section 10 as if it were an Incentive Stock Option,
but a non-statutory Option may also be exercised so long as the optionee
maintains a relationship with the Company as a director, consultant or adviser,
unless the Option Agreement provides otherwise.

     11. INCENTIVE STOCK OPTIONS. Options which are intended to be Incentive
Stock Options shall be subject to the following additional terms and conditions:

         11.1 EXPRESS DESIGNATION. All Incentive Stock Options shall, at the
time of grant, be specifically designated as such in the Option Agreement
covering such Incentive Stock Options.

         11.2 10% SHAREHOLDER. If any employee to whom an Incentive Stock Option
is to be granted is, at the time of the grant of such Option, the owner of stock
possessing more than 10% of the total combined voting power of all classes of
stock of the Company (after taking into account the attribution of stock
ownership rules of Section 424(d) of the Code), then the following special
provisions shall be applicable to the Incentive Stock Option granted to such
individual:

               11.2.1 the purchase price per share of the Common Stock subject
to such Incentive Stock Option shall not be less than 110% of the fair market
value of one share of Common Stock at the time of grant; and

               11.2.2 the option exercise period shall not exceed five years
from the date of grant.

     11.3 DOLLAR LIMITATION. For so long as the Code shall so provide, Options
granted to any employee under the Plan (and any other incentive stock option
plans of the Company) which are intended to constitute Incentive Stock Options
shall not constitute Incentive Stock Options to the extent that such Options, in
the aggregate, become exercisable for the first time in any one calendar year
for shares of Common Stock with an aggregate fair market value (determined as of
the respective date or dates of grant) of more than $100,000.

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     12. ADDITIONAL PROVISIONS.

         12.1 ADDITIONAL PROVISIONS. The Board of Directors may, in its sole
discretion, include additional provisions in Restricted Stock Agreements and
Option Agreements, including, without limitation, restrictions on transfer,
rights of the Company to repurchase shares of Restricted Stock or shares of
Common Stock acquired upon exercise of Options, commitments to pay cash bonuses,
to make, arrange for or guaranty loans or to transfer other property to
optionees upon exercise of Options, or such other provisions as shall be
determined by the Board of Directors; PROVIDED THAT such additional provisions
shall not be inconsistent with any other term or condition of the Plan and such
additional provisions shall not be such as to cause any Incentive Stock Option
to fail to qualify as an Incentive Stock Option within the meaning of Section
422 of the Code.

         12.2 ACCELERATION, EXTENSION, ETC. The Board of Directors may, in its
sole discretion, (i) accelerate the date or dates on which all or any particular
Option or Options may be exercised or (ii) extend the dates during which all, or
any particular, Option or Options may be exercised.

     13. RIGHTS AS A SHAREHOLDER. The holder of an Option shall have no rights
as a shareholder with respect to any shares covered by the Option (including,
without limitation, any rights to receive dividends or non-cash distributions
with respect to such shares) until the date of issue of a stock certificate to
him or her for such shares. No adjustment shall be made for dividends or other
rights for which the record date is prior to the date such stock certificate is
issued.

     14. ADJUSTMENT PROVISIONS FOR RECAPITALIZATIONS AND RELATED TRANSACTIONS.

         14.1 GENERAL. If, through or as a result of any merger, consolidation,
sale of all or substantially all of the assets of the Company, reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split or other similar transaction, (i) the outstanding shares of Common Stock
are increased, decreased or exchanged for a different number or kind of shares
or other securities of the Company, or (ii) additional shares or new or
different shares or other securities of the Company or other non-cash assets are
distributed with respect to such shares of Common Stock or other securities, an
appropriate and proportionate adjustment may be made in (x) the maximum number
and kind of shares reserved for issuance under the Plan, (y) the number and kind
of shares or other securities subject to any then outstanding Options, and (z)
the price for each share subject to any then outstanding Options, without
changing the aggregate purchase price as to which such Options remain
exercisable. Notwithstanding the foregoing, no adjustment shall be made pursuant
to this Section 14 if such adjustment would cause the Plan to fail to comply
with Section 422 of the Code.

         14.2 BOARD AUTHORITY TO MAKE ADJUSTMENTS. Any adjustments under this
Section 14 will be made by the Board of Directors, whose determination as to
what adjustments, if any, will be made and the extent thereof will be final,
binding and conclusive. No fractional shares will be issued under the Plan on
account of any such adjustments.

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     15. MERGER, CONSOLIDATION, ASSET SALE, LIQUIDATION, ETC.

         15.1 GENERAL. In the event of a consolidation or merger or sale of all
or substantially all of the assets of the Company in which outstanding shares of
Common Stock are exchanged for securities, cash or other property of any other
corporation or business entity, or in the event of a liquidation of the Company,
the Board of Directors of the Company, or the board of directors of any
corporation assuming the obligations of the Company, may, in its discretion,
take any one or more of the following actions, as to some or all outstanding
Options (and need not take the same action as to each such Option): (i) provide
that such Options shall be assumed, or equivalent Options shall be substituted,
by the acquiring or succeeding corporation (or an affiliate thereof), PROVIDED
THAT any such Options substituted for Incentive Stock Options shall meet the
requirements of Section 424(a) of the Code, (ii) upon written notice to the
optionees, provide that all unexercised Options will terminate immediately prior
to the consummation of such transaction unless exercised by the optionee (to the
extent otherwise then exercisable) within a specified period following the date
of such notice, (iii) in the event of a merger under the terms of which holders
of the Common Stock of the Company will receive upon consummation thereof a cash
payment for each share surrendered in the merger (the "Merger Price"), make or
provide for a cash payment to the optionees equal to the difference between (A)
the Merger Price times the number of shares of Common Stock subject to such
outstanding Options (to the extent then exercisable at prices not in excess of
the Merger Price) and (B) the aggregate exercise price of all such outstanding
Options, in exchange for the termination of such Options, and (iv) provide that
all or any outstanding Options shall become exercisable in full immediately
prior to such event.

         15.2 SUBSTITUTE OPTIONS. The Company may grant Options in substitution
for Options held by employees of another corporation who become employees of the
Company, or a subsidiary of the Company, as the result of a merger or
consolidation of the employing corporation with the Company or a subsidiary of
the Company, or as a result of the acquisition by the Company, or one of its
subsidiaries, of property or stock of the employing corporation. The Company may
direct that substitute Options be granted on such terms and conditions as the
Board of Directors considers appropriate in the circumstances.

         15.3 RESTRICTED STOCK. In the event of a business combination or other
transaction of the type detailed in Section 15.1, any securities, cash or other
property received in exchange for shares of Restricted Stock shall continue to
be governed by the provisions of any Restricted Stock Agreement pursuant to
which they were issued, including any provision regarding vesting, and such
securities, cash, or other property may be held in escrow on such terms as the
Board of Directors may direct, to insure compliance with the terms of any such
Restricted Stock Agreement.

     16. NO SPECIAL EMPLOYMENT RIGHTS. Nothing contained in the Plan or in any
Option or Grant Stock Agreement shall confer upon any optionee any right with
respect to the continuation of his or her employment by the Company or interfere
in any way with the right of the Company at any time to terminate such
employment or to increase or decrease the compensation of the optionee.

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     17. OTHER EMPLOYEE BENEFITS. The amount of any compensation deemed to be
received by an employee as a result of the issuance of shares of Restricted
Stock or the grant or exercise of an Option or the sale of shares received upon
such award or exercise will not constitute compensation with respect to which
any other employee benefits of such employee are determined, including, without
limitation, benefits under any bonus, pension, profit-sharing, life insurance or
salary continuation plan, except as otherwise specifically determined by the
Board of Directors.

     18. AMENDMENT OF THE PLAN AND AWARDS.

         18.1 The Board of Directors may at any time, and from time to time,
modify or amend the Plan in any respect, except that if at any time the approval
of the shareholders of the Company is required under Section 422 of the Code or
any successor provision with respect to Incentive Stock Options, the Board of
Directors may not effect such modification or amendment without such approval.

         18.2 The Board of Directors may amend, modify or terminate any
outstanding Option or Restricted Stock Award, including but not limited to,
substituting therefore another Option or Restricted Stock Award of the same or a
different type, changing the date of exercise or realization, and converting an
Incentive Stock Option to a Nonstatutory Stock Option, provided that such
holder's or purchaser's consent to such action shall be required unless the
Board of Directors determines that the action, taking into account any related
action, would not materially and adversely affect such holder or purchaser.

         18.3 The Board of Directors shall have the right to amend or modify the
terms and provisions of the Plan and of any outstanding Incentive Stock Options
to the extent necessary to qualify any or all such Options for such favorable
federal income tax treatment (including deferral of taxation upon exercise) as
may be afforded incentive stock options under Section 422 of the Code.

     19. WITHHOLDING. The Company shall have the right to deduct from payments
of any kind otherwise due to the optionee any federal, state or local taxes of
any kind required by law to be withheld with respect to issuance of any shares
of Restricted Stock or shares issued upon exercise of Options. Subject to the
prior approval of the Company, which may be withheld by the Company in its sole
discretion, the obligor may elect to satisfy such minimum withholding
obligations, in whole or in part, (i) by causing the Company to withhold shares
of Common Stock otherwise issuable or (ii) by delivering to the Company shares
of Common Stock already owned by the obligor for a period of at least six
months. The shares so delivered or withheld shall have a fair market value equal
to such withholding obligation. The fair market value of the shares used to
satisfy such withholding obligation shall be determined by the Company as of the
date that the amount of tax to be withheld is to be determined. A person who has
made an election pursuant to this Section 19 may only satisfy his or her
withholding obligation with shares of Common Stock which are not subject to any
repurchase, forfeiture, unfulfilled vesting or other similar requirements.

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     20. EFFECTIVE DATE AND DURATION OF THE PLAN.

         20.1 EFFECTIVE DATE. The Plan shall become effective when adopted by
the Board of Directors, but no Incentive Stock Option shall become exercisable
unless and until the Plan shall have been approved by the Company's
shareholders. If such shareholder approval is not obtained within twelve months
after the date of the Board's adoption of the Plan, no Options previously
granted under the Plan shall be deemed to be Incentive Stock Options and no
Incentive Stock Options shall be granted thereafter. Amendments to the Plan not
requiring shareholder approval shall become effective when adopted by the Board
of Directors; amendments requiring shareholder approval (as provided in Section
18) shall become effective when adopted by the Board of Directors, but no
Incentive Stock Option granted after the date of such amendment shall become
exercisable (to the extent that such amendment to the Plan was required to
enable the Company to grant such Incentive Stock Option to a particular
optionee) unless and until such amendment shall have been approved by the
Company's shareholders. If such shareholder approval is not obtained within
twelve months of the Board's adoption of such amendment, any Incentive Stock
Options granted on or after the date of such amendment shall terminate to the
extent that such amendment to the Plan was required to enable the Company to
grant such Option to a particular optionee. Subject to this limitation, Options
may be granted under the Plan at any time after the effective date and before
the date fixed for termination of the Plan.

         20.2 TERMINATION. Unless sooner terminated in accordance with Section
15 or by the Board of Directors, the Plan shall terminate upon the close of
business on the day next preceding the tenth anniversary of the date of its
adoption by the Board of Directors.

     21. PROVISION FOR FOREIGN PARTICIPANTS. The Board of Directors may, without
amending the Plan, modify the terms of Option or Grant Stock Agreements to
differ from those specified in the Plan with respect to participants who are
foreign nationals or employed outside the United States to recognize differences
in laws, rules, regulations or customs of such foreign jurisdictions with
respect to tax, securities, currency, employee benefit or other matters.

     22. REQUIREMENTS OF LAW. The Company shall not be required to sell or issue
any shares under any Option if the issuance of such shares shall constitute a
violation by the optionee or by the Company of any provisions of any law or
regulation of any governmental authority. In addition, in connection with the
Securities Act, the Company shall not be required to issue any shares upon
exercise of any Option unless the Company has received evidence satisfactory to
it to the effect that the holder of such Option will not transfer such shares
except pursuant to a registration statement in effect under the Act or unless an
opinion of counsel satisfactory to the Company has been received by the Company
to the effect that such registration is not required in connection with any such
transfer. Any determination in this connection by the Board shall be final,
binding and conclusive. In the event the shares issuable on exercise of an
Option are not registered under the Act or under the securities laws of each
relevant state or other jurisdiction, the Company may imprint on the
certificate(s) appropriate legends that counsel for the Company considers
necessary or advisable to comply with the Act or any such state or other
securities law. The Company may register, but in no event shall be obligated to
register, any securities covered by the Plan pursuant to the Act; and in the
event any shares are so registered the Company may remove any legend on
certificates representing such shares. The Company shall not be obligated

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to take any affirmative action in order to cause the exercise of an Option or
the issuance of shares pursuant thereto to comply with any law or regulation of
any governmental authority.

     23. GOVERNING LAW. This Plan and each Option shall be governed by the laws
of the Commonwealth of Massachusetts, without regard to its principles of
conflicts of law.

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