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                                                                    EXHIBIT 10.5


                               EXELIXIS, INC.

               2000 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN

                          Adopted January 27, 2000
                   Approved By Stockholders March 15, 2000

                   Effective Date: Initial Public Offering
                           Termination Date: None

1. PURPOSES.

     (a) Eligible Option Recipients. The persons eligible to receive Options are
the Non-Employee Directors of the Company.

     (b) Available Options. The purpose of the Plan is to provide a means by
which Non-Employee Directors may be given an opportunity to benefit from
increases in value of the Common Stock through the granting of Nonstatutory
Stock Options.

     (c) General Purpose. The Company, by means of the Plan, seeks to retain the
services of its Non-Employee Directors, to secure and retain the services of new
Non-Employee Directors and to provide incentives for such persons to exert
maximum efforts for the success of the Company and its Affiliates.

2. DEFINITIONS.

     (a) "Affiliate" means any parent corporation or subsidiary corporation of
the Company, whether now or hereafter existing, as those terms are defined in
Sections 424(e) and (f), respectively, of the Code.

     (b) "Annual Grant" means an Option granted annually to all Non-Employee
Directors who meet the specified criteria pursuant to subsection 6(b) of the
Plan.

     (c) "Annual Meeting" means the annual meeting of the stockholders of the
Company.

     (d) "Board" means the Board of Directors of the Company.

     (e) "Calculation Date" means the last day of each fiscal year of the
Company.

     (f) "Code" means the Internal Revenue Code of 1986, as amended.

     (g) "Committee" means a committee of one or more members of the Board
appointed by the Board in accordance with subsection 3(c).

     (h) "Common Stock" means the common stock of the Company.
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     (i) "Company" means Exelixis, Inc., a Delaware corporation.

     (j) "Consultant" means any person, including an advisor, (i) engaged by the
Company or an Affiliate to render consulting or advisory services and who is
compensated for such services or (ii) who is a member of the Board of Directors
of an Affiliate. However, the term "Consultant" shall not include either
Directors of the Company who are not compensated by the Company for their
services as Directors or Directors of the Company who are merely paid a
director's fee by the Company for their services as Directors.

     (k) "Continuous Service" means that the Optionholder's service with the
Company or an Affiliate, whether as an Employee, Director or Consultant, is not
interrupted or terminated. The Optionholder's Continuous Service shall not be
deemed to have terminated merely because of a change in the capacity in which
the Optionholder renders service to the Company or an Affiliate as an Employee,
Consultant or Director or a change in the entity for which the Optionholder
renders such service, provided that there is no interruption or termination of
the Optionholder's Continuous Service. For example, a change in status from a
Non-Employee Director of the Company to a Consultant of an Affiliate or an
Employee of the Company will not constitute an interruption of Continuous
Service. The Board or the chief executive officer of the Company, in that
party's sole discretion, may determine whether Continuous Service shall be
considered interrupted in the case of any leave of absence approved by that
party, including sick leave, military leave or any other personal leave.

     (l) "Diluted Shares Outstanding" means the number of outstanding shares of
Common Stock on the Calculation Date, plus the number of shares of Common Stock
issuable on the Calculation Date assuming the conversion of all outstanding
preferred stock and convertible notes, and the additional number of dilutive
Common Stock equivalent shares outstanding as the result of any options or
warrants outstanding during the fiscal year, calculated using the treasury stock
method.

     (m) "Director" means a member of the Board of Directors of the Company.

     (n) "Disability" means the permanent and total disability of a person
within the meaning of Section 22(e)(3) of the Code.

     (o) "Employee" means any person employed by the Company or an Affiliate.
Mere service as a Director or payment of a director's fee by the Company or an
Affiliate shall not be sufficient to constitute "employment" by the Company or
an Affiliate.

     (p) "Exchange Act" means the Securities Exchange Act of 1934, as amended.

     (q) "Fair Market Value" means, as of any date, the value of the Common
Stock determined as follows:

         (i) If the Common Stock is listed on any established stock exchange or
traded on the Nasdaq National Market or the Nasdaq SmallCap Market, the Fair
Market Value of a share of Common Stock shall be the closing sales price for
such stock (or the closing bid, if no

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sales were reported) as quoted on such exchange or market (or the exchange or
market with the greatest volume of trading in the Common Stock) on the last
market trading day prior to the day of determination, as reported in The Wall
Street Journal or such other source as the Board deems reliable.

         (ii) In the absence of such markets for the Common Stock, the Fair
Market Value shall be determined in good faith by the Board.

     (r) "Initial Grant" means an Option granted to a Non-Employee Director who
meets the specified criteria pursuant to subsection 6(a) of the Plan.

     (s) "IPO Date" means the effective date of the initial public offering of
the Common Stock.

     (t) "Non-Employee Director" means a Director who is not an Employee.

     (u) "Nonstatutory Stock Option" means an Option not intended to qualify as
an incentive stock option within the meaning of Section 422 of the Code and the
regulations promulgated thereunder.

     (v) "Officer" means a person who is an officer of the Company within the
meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

     (w) "Option" means a Nonstatutory Stock Option granted pursuant to the
Plan.

     (x) "Option Agreement" means a written agreement between the Company and an
Optionholder evidencing the terms and conditions of an individual Option grant.
Each Option Agreement shall be subject to the terms and conditions of the Plan.

     (y) "Optionholder" means a person to whom an Option is granted pursuant to
the Plan or, if applicable, such other person who holds an outstanding Option.

     (z) "Plan" means this Exelixis, Inc. 2000 Non-Employee Directors' Stock
Option Plan.

     (aa) "Rule 16b-3" means Rule 16b-3 promulgated under the Exchange Act or
any successor to Rule 16b-3, as in effect from time to time.

     (bb) "Securities Act" means the Securities Act of 1933, as amended.

3. ADMINISTRATION.

     (a) Administration by Board. The Board shall administer the Plan unless and
until the Board delegates administration to a Committee, as provided in
subsection 3(c).

     (b) Powers of Board. The Board shall have the power, subject to, and within
the limitations of, the express provisions of the Plan:

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         (i) To determine the provisions of each Option to the extent not
specified in the Plan.

         (ii) To construe and interpret the Plan and Options granted under it,
and to establish, amend and revoke rules and regulations for its administration.
The Board, in the exercise of this power, may correct any defect, omission or
inconsistency in the Plan or in any Option Agreement, in a manner and to the
extent it shall deem necessary or expedient to make the Plan fully effective.

         (iii) To amend the Plan or an Option as provided in Section 12.

         (iv) Generally, to exercise such powers and to perform such acts as the
Board deems necessary or expedient to promote the best interests of the Company
that are not in conflict with the provisions of the Plan.

     (c) Delegation to Committee. The Board may delegate administration of the
Plan to a Committee or Committees of one (1) or more members of the Board, and
the term "Committee" shall apply to any person or persons to whom such authority
has been delegated. If administration is delegated to a Committee, the Committee
shall have, in connection with the administration of the Plan, the powers
theretofore possessed by the Board, including the power to delegate to a
subcommittee any of the administrative powers the Committee is authorized to
exercise (and references in this Plan to the Board shall thereafter be to the
Committee or subcommittee), subject, however, to such resolutions, not
inconsistent with the provisions of the Plan, as may be adopted from time to
time by the Board. The Board may abolish the Committee at any time and revest in
the Board the administration of the Plan.

     (d) Effect of Board's Decision. All determinations, interpretations and
constructions made by the Board in good faith shall not be subject to review by
any person and shall be final, binding and conclusive on all persons.

4. SHARES SUBJECT TO THE PLAN.

     (a) Share Reserve. Subject to the provisions of subsection 4(b) relating to
automatic increases to the share reserve, the provisions of subsection 4(c)
relating to reversion of shares of Common Stock to the share reserve and the
provisions of Section 11 relating to adjustments upon changes in the Common
Stock, the Common Stock that may be issued pursuant to Stock Awards shall not
exceed in the aggregate Five Hundred Thousand (500,000) shares of Common Stock.

     (b) Automatic Increase. For a period of ten (10) years, the share reserve
specified in subsection 4(a) automatically shall be increased on the Calculation
Date by the greater of that number of shares of Common Stock equal to 0.75% of
the Diluted Shares Outstanding or that number of shares of Common Stock that
have been made subject to Options granted under the Plan during the prior
12-month period; provided, however, that the Board may provide for a lesser
number at any time prior to the Calculation Date.

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     (c) Reversion of Shares to the Share Reserve. If any Option shall for any
reason expire or otherwise terminate, in whole or in part, without having been
exercised in full, the shares of Common Stock not acquired under such Option
shall revert to and again become available for issuance under the Plan. If the
Company repurchases any unvested shares of Common Stock acquired under the Plan,
the repurchased shares of Common Stock shall revert to and again become
available for issuance under the Plan.

     (d) Source of Shares. The shares of Common Stock subject to the Plan may be
unissued shares or reacquired shares, bought on the market or otherwise.

5. ELIGIBILITY.

     The Options as set forth in section 6 automatically shall be granted under
the Plan to all Non-Employee Directors.

6. NON-DISCRETIONARY GRANTS.

     (a) Initial Grants. Without any further action of the Board, each
Non-Employee Director shall be granted the following Options:

         (i) On the IPO Date, each person who is then a Non-Employee Director
automatically shall be granted an Initial Grant to purchase Twenty-five Thousand
(25,000) shares of Common Stock on the terms and conditions set forth herein.

         (ii) After the IPO Date, each person who is elected or appointed for
the first time to be a Non-Employee Director automatically shall, upon the date
of his or her initial election or appointment to be a Non-Employee Director by
the Board or stockholders of the Company, be granted an Initial Grant to
purchase Twenty-five Thousand (25,000) shares of Common Stock on the terms and
conditions set forth herein.

     (b) Annual Grants. On the day following each Annual Meeting each person who
is then a Non-Employee Director automatically shall be granted an Annual Grant
to purchase Five Thousand (5,000) shares of Common Stock on the terms and
conditions set forth herein.

7. OPTION PROVISIONS.

     Each Option shall be in such form and shall contain such terms and
conditions as required by the Plan. Each Option shall contain such additional
terms and conditions, not inconsistent with the Plan, as the Board shall deem
appropriate. Each Option shall include (through incorporation of provisions
hereof by reference in the Option or otherwise) the substance of each of the
following provisions:

     (a) Term. No Option shall be exercisable after the expiration of ten (10)
years from the date it was granted.

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     (b) Exercise Price. The exercise price of each Option shall be one hundred
percent (100%) of the Fair Market Value of the stock subject to the Option on
the date the Option is granted. Notwithstanding the foregoing, an Option may be
granted with an exercise price lower than that set forth in the preceding
sentence if such Option is granted pursuant to an assumption or substitution for
another option in a manner satisfying the provisions of Section 424(a) of the
Code.

     (c) Consideration. The purchase price of Common Stock acquired pursuant to
an Option shall be paid, to the extent permitted by applicable statutes and
regulations, either (i) in cash at the time the Option is exercised or (ii) at
the discretion of the Board at the time of the grant of the Option or
subsequently (1) by delivery to the Company of other Common Stock, (2) according
to a deferred payment or other similar arrangement with the Optionholder or (3)
in any other form of legal consideration that may be acceptable to the Board.
Unless otherwise specifically provided in the Option, the purchase price of
Common Stock acquired pursuant to an Option that is paid by delivery to the
Company of other Common Stock acquired, directly or indirectly from the Company,
shall be paid only by shares of the Common Stock of the Company that have been
held for more than six (6) months (or such longer or shorter period of time
required to avoid a charge to earnings for financial accounting purposes). At
any time that the Company is incorporated in Delaware, payment of the Common
Stock's "par value," as defined in the Delaware General Corporation Law, shall
not be made by deferred payment.

     In the case of any deferred payment arrangement, interest shall be
compounded at least annually and shall be charged at the minimum rate of
interest necessary to avoid the treatment as interest, under any applicable
provisions of the Code, of any amounts other than amounts stated to be interest
under the deferred payment arrangement.

     (d) Transferability. An Option shall not be transferable except by will or
by the laws of descent and distribution and to such further extent as permitted
by the Rule as to Use of Form S-8 specified in the General Instructions of the
Form S-8 Registration Statement under the Securities Act, and shall be
exercisable during the lifetime of the Optionholder only by the Optionholder.
Notwithstanding the foregoing, the Optionholder may, by delivering written
notice to the Company, in a form satisfactory to the Company, designate a third
party who, in the event of the death of the Optionholder, shall thereafter be
entitled to exercise the Option.

     (e) Exercise and Vesting. Options shall be exercisable immediately upon
grant. Options shall vest as follows:

         (i) Initial Grants shall provide for vesting of 1/4th of the shares 12
months after the date of the grant and 1/48th of the shares each month
thereafter.

         (ii) Annual Grants shall provide for vesting of 1/12th of the shares
each month after the date of the grant.

     (f) Termination of Continuous Service. In the event an Optionholder's
Continuous Service terminates (other than upon the Optionholder's death or
Disability), the Optionholder may exercise his or her Option (to the extent that
the Optionholder was entitled to exercise it as

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of the date of termination) but only within such period of time ending on the
earlier of (i) the date three (3) months following the termination of the
Optionholder's Continuous Service, or (ii) the expiration of the term of the
Option as set forth in the Option Agreement. If, after termination, the
Optionholder does not exercise his or her Option within the time specified in
the Option Agreement, the Option shall terminate.

     (g) Extension of Termination Date. If the exercise of the Option following
the termination of the Optionholder's Continuous Service (other than upon the
Optionholder's death or Disability) would be prohibited at any time solely
because the issuance of shares would violate the registration requirements under
the Securities Act, then the Option shall terminate on the earlier of (i) the
expiration of the term of the Option set forth in subsection 7(a) or (ii) the
expiration of a period of three (3) months after the termination of the
Optionholder's Continuous Service during which the exercise of the Option would
not be in violation of such registration requirements.

     (h) Disability of Optionholder. In the event an Optionholder's Continuous
Service terminates as a result of the Optionholder's Disability, the
Optionholder may exercise his or her Option (to the extent that the Optionholder
was entitled to exercise it as of the date of termination), but only within such
period of time ending on the earlier of (i) the date twelve (12) months
following such termination or (ii) the expiration of the term of the Option as
set forth in the Option Agreement. If, after termination, the Optionholder does
not exercise his or her Option within the time specified herein, the Option
shall terminate.

     (i) Death of Optionholder. In the event (i) an Optionholder's Continuous
Service terminates as a result of the Optionholder's death or (ii) the
Optionholder dies within the three-month period after the termination of the
Optionholder's Continuous Service for a reason other than death, then the Option
may be exercised (to the extent the Optionholder was entitled to exercise the
Option as of the date of death) by the Optionholder's estate, by a person who
acquired the right to exercise the Option by bequest or inheritance or by a
person designated to exercise the Option upon the Optionholder's death, but only
within the period ending on the earlier of (1) the date eighteen (18) months
following the date of death or (2) the expiration of the term of such Option as
set forth in the Option Agreement. If, after death, the Option is not exercised
within the time specified herein, the Option shall terminate.

8. COVENANTS OF THE COMPANY.

     (a) Availability of Shares. During the terms of the Options, the Company
shall keep available at all times the number of shares of Common Stock required
to satisfy such Options.

     (b) Securities Law Compliance. The Company shall seek to obtain from each
regulatory commission or agency having jurisdiction over the Plan such authority
as may be required to grant Options and to issue and sell shares of Common Stock
upon exercise of the Options; provided, however, that this undertaking shall not
require the Company to register under the Securities Act the Plan, any Option or
any stock issued or issuable pursuant to any such Option. If, after reasonable
efforts, the Company is unable to obtain from any such regulatory commission or
agency the authority which counsel for the Company deems necessary

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for the lawful issuance and sale of stock under the Plan, the Company shall be
relieved from any liability for failure to issue and sell stock upon exercise of
such Options unless and until such authority is obtained.

9. USE OF PROCEEDS FROM STOCK.

     Proceeds from the sale of stock pursuant to Options shall constitute
general funds of the Company.

10. MISCELLANEOUS.

     (a) Stockholder Rights. No Optionholder shall be deemed to be the holder
of, or to have any of the rights of a holder with respect to, any shares subject
to such Option unless and until such Optionholder has satisfied all requirements
for exercise of the Option pursuant to its terms.

     (b) No Service Rights. Nothing in the Plan or any instrument executed or
Option granted pursuant thereto shall confer upon any Optionholder any right to
continue to serve the Company as a Non-Employee Director or shall affect the
right of the Company or an Affiliate to terminate (i) the employment of an
Employee with or without notice and with or without cause, (ii) the service of a
Consultant pursuant to the terms of such Consultant's agreement with the Company
or an Affiliate or (iii) the service of a Director pursuant to the Bylaws of the
Company or an Affiliate, and any applicable provisions of the corporate law of
the state in which the Company or the Affiliate is incorporated, as the case may
be.

     (c) Investment Assurances. The Company may require an Optionholder, as a
condition of exercising or acquiring stock under any Option, (i) to give written
assurances satisfactory to the Company as to the Optionholder's knowledge and
experience in financial and business matters and/or to employ a purchaser
representative reasonably satisfactory to the Company who is knowledgeable and
experienced in financial and business matters and that he or she is capable of
evaluating, alone or together with the purchaser representative, the merits and
risks of exercising the Option; and (ii) to give written assurances satisfactory
to the Company stating that the Optionholder is acquiring the stock subject to
the Option for the Optionholder's own account and not with any present intention
of selling or otherwise distributing the stock. The foregoing requirements, and
any assurances given pursuant to such requirements, shall be inoperative if
(iii) the issuance of the shares upon the exercise or acquisition of stock under
the Option has been registered under a then currently effective registration
statement under the Securities Act or (iv) as to any particular requirement, a
determination is made by counsel for the Company that such requirement need not
be met in the circumstances under the then applicable securities laws. The
Company may, upon advice of counsel to the Company, place legends on stock
certificates issued under the Plan as such counsel deems necessary or
appropriate in order to comply with applicable securities laws, including, but
not limited to, legends restricting the transfer of the stock.

     (d) Withholding Obligations. The Optionholder may satisfy any federal,
state or local tax withholding obligation relating to the exercise or
acquisition of stock under an Option

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by any of the following means (in addition to the Company's right to withhold
from any compensation paid to the Optionholder by the Company) or by a
combination of such means: (i) tendering a cash payment; (ii) authorizing the
Company to withhold shares from the shares of the Common Stock otherwise
issuable to the Optionholder as a result of the exercise or acquisition of stock
under the Option, provided, however, that no shares of Common Stock are withheld
with a value exceeding the minimum amount of tax required to be withheld by law;
or (iii) delivering to the Company owned and unencumbered shares of the Common
Stock.

11. ADJUSTMENTS UPON CHANGES IN STOCK.

     (a) Capitalization Adjustments. If any change is made in the stock subject
to the Plan, or subject to any Option, without the receipt of consideration by
the Company (through merger, consolidation, reorganization, recapitalization,
reincorporation, stock dividend, dividend in property other than cash, stock
split, liquidating dividend, combination of shares, exchange of shares, change
in corporate structure or other transaction not involving the receipt of
consideration by the Company), the Plan will be appropriately adjusted in the
class(es) and maximum number of securities subject both to the Plan pursuant to
subsection 4(a) and to the nondiscretionary Options specified in Section 5, and
the outstanding Options will be appropriately adjusted in the class(es) and
number of securities and price per share of stock subject to such outstanding
Options. The Board shall make such adjustments, and its determination shall be
final, binding and conclusive. (The conversion of any convertible securities of
the Company shall not be treated as a transaction "without receipt of
consideration" by the Company.)

     (b) Change in Control--Dissolution or Liquidation. In the event of a
dissolution or liquidation of the Company, then all outstanding Options shall
terminate immediately prior to such event.

     (c) Change in Control--Asset Sale, Merger, Consolidation or Reverse Merger.
In the event of (i) a sale, lease or other disposition of all or substantially
all of the assets of the Company, (ii) a merger or consolidation in which the
Company is not the surviving corporation or (iii) a reverse merger in which the
Company is the surviving corporation but the shares of Common Stock outstanding
immediately preceding the merger are converted by virtue of the merger into
other property, whether in the form of securities, cash or otherwise, then any
surviving corporation or acquiring corporation shall assume any Options
outstanding under the Plan or shall substitute similar options (including an
option to acquire the same consideration paid to the stockholders in the
transaction described in this subsection 11(c) for those outstanding under the
Plan). In the event any surviving corporation or acquiring corporation refuses
to assume such Options or to substitute similar options for those outstanding
under the Plan, then with respect to Options held by Optionholders whose
Continuous Service has not terminated, the vesting of such Options and any
shares of Common Stock acquired under such Options (and, if applicable, the time
during which such Options may be exercised) shall be accelerated in full, and
the Options shall terminate if not exercised at or prior to such event. With
respect to any other Options outstanding under the Plan, such Options shall
terminate if not exercised prior to such event.

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     (d) Change in Control--Securities Acquisition. In the event of an
acquisition by any person, entity or group within the meaning of Section 13(d)
or 14(d) of the Exchange Act, or any comparable successor provisions (excluding
any employee benefit plan, or related trust, sponsored or maintained by the
Company or an Affiliate) of the beneficial ownership (within the meaning of Rule
13d-3 promulgated under the Exchange Act, or comparable successor rule) of
securities of the Company representing at least fifty percent (50%) of the
combined voting power entitled to vote in the election of Directors and provided
that such acquisition is not a result of, and does not constitute a transaction
described in, subsection 11(c) hereof, then with respect to Options held by
Optionholders whose Continuous Service has not terminated, the vesting of such
Options and any shares of Common Stock acquired under such Options (and, if
applicable, the time during which such Options may be exercised) shall be
accelerated in full.

12. AMENDMENT OF THE PLAN AND OPTIONS.

     (a) Amendment of Plan. The Board at any time, and from time to time, may
amend the Plan. However, except as provided in Section 11 relating to
adjustments upon changes in stock, no amendment shall be effective unless
approved by the stockholders of the Company to the extent stockholder approval
is necessary to satisfy the requirements of Rule 16b-3 or any Nasdaq or
securities exchange listing requirements.

     (b) Stockholder Approval. The Board may, in its sole discretion, submit any
other amendment to the Plan for stockholder approval.

     (c) No Impairment of Rights. Rights under any Option granted before
amendment of the Plan shall not be impaired by any amendment of the Plan unless
(i) the Company requests the consent of the Optionholder and (ii) the
Optionholder consents in writing.

     (d) Amendment of Options. The Board at any time, and from time to time, may
amend the terms of any one or more Options; provided, however, that the rights
under any Option shall not be impaired by any such amendment unless (i) the
Company requests the consent of the Optionholder and (ii) the Optionholder
consents in writing.

13. TERMINATION OR SUSPENSION OF THE PLAN.

     (a) Plan Term. The Board may suspend or terminate the Plan at any time. No
Options may be granted under the Plan while the Plan is suspended or after it is
terminated.

     (b) No Impairment of Rights. Suspension or termination of the Plan shall
not impair rights and obligations under any Option granted while the Plan is in
effect except with the written consent of the Optionholder.

14. EFFECTIVE DATE OF PLAN.

     The Plan shall become effective on the IPO Date, but no Option shall be
exercised unless and until the Plan has been approved by the stockholders of the
Company, which approval shall be within twelve (12) months before or after the
date the Plan is adopted by the Board.

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15. CHOICE OF LAW.

     All questions concerning the construction, validity and interpretation of
this Plan shall be governed by the law of the State of Delaware, without regard
to such state's conflict of laws rules.

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