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                                                                    Exhibit 10.4

                                  GENVEC, INC.
                            2000 DIRECTOR OPTION PLAN
                           (As Amended March 14, 2001)

         1.  PURPOSES OF THE PLAN. The purposes of this 2000 Director Option
Plan are to attract and retain the best available personnel for service as
Outside Directors (as defined herein) of the Company, to provide additional
incentive to the Outside Directors of the Company to serve as Directors, and to
encourage their continued service on the Board.

         All options granted hereunder shall be nonstatutory stock options.

         2.  DEFINITIONS.  As used herein, the following definitions shall
apply:

             (a)      "BOARD" means the Board of Directors of the Company.

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

             (c)      "COMMON STOCK" means the common stock of the Company.

             (d)      "COMPANY" means GenVec, Inc., a Delaware corporation.

             (e)      "DIRECTOR" means a member of the Board.

             (f)      "DISABILITY" means total and permanent disability as
defined in section 22(e)(3) of the Code.

             (g)      "EMPLOYEE" means any person, including officers and
Directors, employed by the Company or any Parent or Subsidiary of the Company.
The payment of a Director's fee by the Company shall not be sufficient in and of
itself to constitute "employment" by the Company.

             (h)      "EXCHANGE ACT" means the Securities Exchange Act of
1934, as amended.

             (i)      "FAIR MARKET VALUE" means, as of any date, the value
of Common Stock determined as follows:

                      (i)     If the Common Stock is listed on any established
stock exchange or a national market system, including without limitation the
Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market,
its Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to

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the time of determination as reported in THE WALL STREET JOURNAL or such other
source as the Board deems reliable;

                      (ii)    If the Common Stock is regularly quoted by a
recognized securities dealer but selling prices are not reported, the Fair
Market Value of a Share of Common Stock shall be the mean between the high bid
and low asked prices for the Common Stock for the last market trading day prior
to the time of determination, as reported in THE WALL STREET JOURNAL or such
other source as the Board deems reliable; or

                      (iii)   In the absence of an established market for the
Common Stock, the Fair Market Value thereof shall be determined in good faith by
the Board.

             (j)      "INSIDE DIRECTOR" means a Director who is an Employee.

             (k)      "OPTION" means a stock option granted pursuant to the
Plan.

             (l)      "OPTIONED STOCK" means the Common Stock subject to an
Option.

             (m)      "OPTIONEE" means a Director who holds an Option.

             (n)      "OUTSIDE DIRECTOR" means a Director who is not an
Employee.

             (o)      "PARENT" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

             (p)      "PLAN"  means this 2000 Director Option Plan.

             (q)      "SHARE" means a share of the Common Stock, as
adjusted in accordance with Section 10 of the Plan.

             (r)      "SUBSIDIARY" means a "subsidiary corporation," whether
now or hereafter existing, as defined in Section 424(f) of the Internal Revenue
Code of 1986.

         3.  STOCK SUBJECT TO THE PLAN. Subject to the provisions of
Section 10 of the Plan, the maximum aggregate number of Shares which may be
optioned and sold under the Plan is 350,000 Shares (the "Pool"). The Shares may
be authorized, but unissued, or reacquired Common Stock.

         If an Option expires or becomes unexercisable without having been
exercised in full, the unpurchased Shares which were subject thereto shall
become available for future grant or sale under the Plan (unless the Plan has
terminated). Shares that have actually been issued under the Plan shall not be
returned to the Plan and shall not become available for future distribution
under the Plan.

         4.  ADMINISTRATION AND GRANTS OF OPTIONS UNDER THE PLAN.

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             (a)      PROCEDURE FOR GRANTS. All grants of Options to Outside
Directors under this Plan shall be automatic and nondiscretionary and shall be
made strictly in accordance with the following provisions:

                      (i)     No person shall have any discretion to
select which Outside Directors shall be granted Options or to determine the
number of Shares to be covered by Options.

                      (ii)    After the effective date of this Plan, each
Outside Director shall be automatically granted an Option to purchase 20,000
Shares (the "First Option") on the date on which such person first becomes an
Outside Director, whether through election by the shareholders of the Company or
appointment by the Board to fill a vacancy; provided, however, that on the
effective date of the amendment to this Plan each Outside Director then in
office shall be granted a supplemental First Option for 10,000 Shares on such
date; provided further, however, that an Inside Director who ceases to be an
Inside Director but who remains a Director shall not receive a First Option.

                      (iii)   Each Outside Director shall be automatically
granted an Option to purchase 6,000 Shares (a "Subsequent Option") on the date
of the annual stockholders' meetings of each year, provided he or she is then an
Outside Director and if as of such date, he or she shall have served on the
Board for at least the preceding six (6) months.

                      (iv)    Notwithstanding the provisions of subsections
(ii) and (iii) hereof, any exercise of an Option granted before the Company has
obtained shareholder approval of the Plan in accordance with Section 16 hereof
shall be conditioned upon obtaining such shareholder approval of the Plan in
accordance with Section 16 hereof.

                      (v)     The terms of a First Option granted hereunder
shall be as follows:

                              (A) the term of the First Option shall
be ten (10) years.

                              (B) the First Option shall be exercisable only
while the Outside Director remains a Director of the Company, except as set
forth in Sections 8 and 10 hereof.

                              (C) the exercise price per Share shall be 100%
of the Fair Market Value per Share on the date of grant of the First Option.

                              (D) subject to Section 10 hereof, the First
Option shall become exercisable as to 25 percent of the Shares subject to the
First Option on each anniversary of its date of grant, provided that the
Optionee continues to serve as a Director on such dates.

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                      (vi)    The terms of a Subsequent Option granted
hereunder shall be as follows:

                              (A) the term of the Subsequent Option shall
be ten (10) years.

                              (B) the Subsequent Option shall be exercisable
only while the Outside Director remains a Director of the Company, except as set
forth in Sections 8 and 10 hereof.

                              (C) the exercise price per Share shall be 100%
of the Fair Market Value per Share on the date of grant of the Subsequent
Option.

                              (D) subject to Section 10 hereof, the
Subsequent Option shall become exercisable as to 25 percent of the Shares
subject to the Subsequent Option on each anniversary of its date of grant,
provided that the Optionee continues to serve as a Director on such dates.

                      (vii)   Each Outside Director shall be automatically
granted an Option to purchase 3,000 Shares (an "Additional Option") for each
committee of the Board of Directors on which such Outside Director serves on the
date of his or her appointment or reappointment to a committee. An Additional
Option shall have terms identical to a Subsequent Option as specified above.

                      (viii)  In the event that any Option granted under
the Plan would cause the number of Shares subject to outstanding Options plus
the number of Shares previously purchased under Options to exceed the Pool, then
the remaining Shares available for Option grant shall be granted under Options
to the Outside Directors on a pro rata basis. No further grants shall be made
until such time, if any, as additional Shares become available for grant under
the Plan through action of the Board or the shareholders to increase the number
of Shares which may be issued under the Plan or through cancellation or
expiration of Options previously granted hereunder.

         5.  ELIGIBILITY.  Options may be granted only to Outside Directors.
All Options shall be automatically granted in accordance with the terms set
forth in Section 4 hereof.

         The Plan shall not confer upon any Optionee any right with respect to
continuation of service as a Director or nomination to serve as a Director, nor
shall it interfere in any way with any rights which the Director or the Company
may have to terminate the Director's relationship with the Company at any time.

         6.  TERM OF PLAN. The Plan shall become effective upon the earlier
to occur of its adoption by the Board or its approval by the shareholders of the
Company as described in Section 16 of the Plan. It shall continue in effect for
a term of ten (10) years unless sooner terminated under Section 11 of the Plan.

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         7.  FORM OF CONSIDERATION. The consideration to be paid for the
Shares to be issued upon exercise of an Option, including the method of payment,
shall consist of (i) cash, (ii) check, (iii) other shares which (x) in the case
of Shares acquired upon exercise of an option, have been owned by the Optionee
for more than six (6) months on the date of surrender, and (y) have a Fair
Market Value on the date of surrender equal to the aggregate exercise price of
the Shares as to which said Option shall be exercised, (iv) consideration
received by the Company under a cashless exercise program implemented by the
Company in connection with the Plan, or (v) any combination of the foregoing
methods of payment.

         8.  EXERCISE OF OPTION.

             (a)      PROCEDURE FOR EXERCISE; RIGHTS AS A SHAREHOLDER. Any
Option granted hereunder shall be exercisable at such times as are set forth in
Section 4 hereof; provided, however, that no Options shall be exercisable until
shareholder approval of the Plan in accordance with Section 16 hereof has been
obtained.

         An Option may not be exercised for a fraction of a Share.

         An Option shall be deemed to be exercised when written notice of such
exercise has been given to the Company in accordance with the terms of the
Option by the person entitled to exercise the Option and full payment for the
Shares with respect to which the Option is exercised has been received by the
Company. Full payment may consist of any consideration and method of payment
allowable under Section 7 of the Plan. Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the stock certificate evidencing such Shares, no right
to vote or receive dividends or any other rights as a shareholder shall exist
with respect to the Optioned Stock, notwithstanding the exercise of the Option.
A share certificate for the number of Shares so acquired shall be issued to the
Optionee as soon as practicable after exercise of the Option. No adjustment
shall be made for a dividend or other right for which the record date is prior
to the date the stock certificate is issued, except as provided in Section 10 of
the Plan.

         Exercise of an Option in any manner shall result in a decrease in the
number of Shares which thereafter may be available, both for purposes of the
Plan and for sale under the Option, by the number of Shares as to which the
Option is exercised.

             (b)      TERMINATION OF CONTINUOUS STATUS AS A DIRECTOR. Subject to
Section 10 hereof, in the event an Optionee's status as a Director terminates
(other than upon the Optionee's death or Disability), the Optionee may exercise
his or her Option, but only within three (3) months following the date of such
termination, and only to the extent that the Optionee was entitled to exercise
it on the date of such termination (but in no event later than the expiration of
its ten (10) year term). To the extent that the Optionee was not entitled to
exercise an Option on the date of such termination, and to the extent that

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the Optionee does not exercise such Option (to the extent otherwise so entitled)
within the time specified herein, the Option shall terminate.

             (c)      DISABILITY OF OPTIONEE. In the event Optionee's
status as a Director terminates as a result of Disability, the Optionee may
exercise his or her Option, but only within twelve (12) months following the
date of such termination, and only to the extent that the Optionee was entitled
to exercise it on the date of such termination (but in no event later than the
expiration of its ten (10) year term). To the extent that the Optionee was not
entitled to exercise an Option on the date of termination, or if he or she does
not exercise such Option (to the extent otherwise so entitled) within the time
specified herein, the Option shall terminate.

             (d)      DEATH OF OPTIONEE. In the event of an Optionee's
death, the Optionee's estate or a person who acquired the right to exercise the
Option by bequest or inheritance may exercise the Option, but only within twelve
(12) months following the date of death, and only to the extent that the
Optionee was entitled to exercise it on the date of death (but in no event later
than the expiration of its ten (10) year term). To the extent that the Optionee
was not entitled to exercise an Option on the date of death, and to the extent
that the Optionee's estate or a person who acquired the right to exercise such
Option does not exercise such Option (to the extent otherwise so entitled)
within the time specified herein, the Option shall terminate.

         9.  NON-TRANSFERABILITY OF OPTIONS. The Option may not be sold,
pledged, assigned, hypothecated, transferred, or disposed of in any manner other
than by will or by the laws of descent or distribution and may be exercised,
during the lifetime of the Optionee, only by the Optionee.

         10. ADJUSTMENTS UPON CHANGES IN CAPITALIZATION, DISSOLUTION, MERGER OR
ASSET SALE.

             (a)      CHANGES IN CAPITALIZATION. Subject to any required action
by the shareholders of the Company, the number of Shares covered by each
outstanding Option, the number of Shares which have been authorized for issuance
under the Plan but as to which no Options have yet been granted or which have
been returned to the Plan upon cancellation or expiration of an Option, as well
as the price per Share covered by each such outstanding Option, and the number
of Shares issuable pursuant to the automatic grant provisions of Section 4
hereof shall be proportionately adjusted for any increase or decrease in the
number of issued Shares resulting from a stock split, reverse stock split, stock
dividend, combination or reclassification of the Common Stock, or any other
increase or decrease in the number of issued Shares effected without receipt of
consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration." Except as expressly provided herein, no
issuance by the Company of shares of stock of any class, or securities
convertible into shares of stock of any class, shall affect, and no adjustment
by reason thereof shall be made with respect to, the number or price of Shares
subject to an Option.

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             (b)      DISSOLUTION OR LIQUIDATION. In the event of the proposed
dissolution or liquidation of the Company, to the extent that an Option has not
been previously exercised, it shall terminate immediately prior to the
consummation of such proposed action.

             (c)      MERGER OR ASSET SALE. In the event of a merger of the
Company with or into another corporation or the sale of substantially all of the
assets of the Company, outstanding Options may be assumed or equivalent options
may be substituted by the successor corporation or a Parent or Subsidiary
thereof (the "Successor Corporation"). If an Option is assumed or substituted
for, the Option or equivalent option shall continue to be exercisable as
provided in Section 4 hereof for so long as the Optionee serves as a Director or
a director of the Successor Corporation. Following such assumption or
substitution, if the Optionee's status as a Director or director of the
Successor Corporation, as applicable, is terminated other than upon a voluntary
resignation by the Optionee, the Option or option shall become fully
exercisable, including as to Shares for which it would not otherwise be
exercisable. Thereafter, the Option or option shall remain exercisable in
accordance with Sections 8(b) through (d) above.

         If the Successor Corporation does not assume an outstanding Option or
substitute for it an equivalent option, the Option shall become fully vested and
exercisable, including as to Shares for which it would not otherwise be
exercisable. In such event the Board shall notify the Optionee that the Option
shall be fully exercisable for a period of thirty (30) days from the date of
such notice, and upon the expiration of such period the Option shall terminate.

         For the purposes of this Section 10(c), an Option shall be considered
assumed if, following the merger or sale of assets, the Option confers the right
to purchase or receive, for each Share of Optioned Stock subject to the Option
immediately prior to the merger or sale of assets, the consideration (whether
stock, cash, or other securities or property) received in the merger or sale of
assets by holders of Common Stock for each Share held on the effective date of
the transaction (and if holders were offered a choice of consideration, the type
of consideration chosen by the holders of a majority of the outstanding Shares).
If such consideration received in the merger or sale of assets is not solely
common stock of the successor corporation or its Parent, the Administrator may,
with the consent of the successor corporation, provide for the consideration to
be received upon the exercise of the Option, for each Share of Optioned Stock
subject to the Option, to be solely common stock of the successor corporation or
its Parent equal in fair market value to the per share consideration received by
holders of Common Stock in the merger or sale of assets.

         11. AMENDMENT AND TERMINATION OF THE PLAN.

             (a)      AMENDMENT AND TERMINATION. The Board may at any time
amend, alter, suspend, or discontinue the Plan, but no amendment, alteration,
suspension, or

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discontinuation shall be made which would impair the rights of any Optionee
under any grant theretofore made, without his or her consent. In addition, to
the extent necessary and desirable to comply with any applicable law, regulation
or stock exchange rule, the Company shall obtain shareholder approval of any
Plan amendment in such a manner and to such a degree as required.

             (b)      EFFECT OF AMENDMENT OR TERMINATION. Any such amendment or
termination of the Plan shall not affect Options already granted and such
Options shall remain in full force and effect as if this Plan had not been
amended or terminated.

         12. TIME OF GRANTING OPTIONS.  The date of grant of an Option
shall, for all purposes, be the date determined in accordance with Section 4
hereof.

         13. CONDITIONS UPON ISSUANCE OF SHARES. Shares shall not be issued
pursuant to the exercise of an Option unless the exercise of such Option and the
issuance and delivery of such Shares pursuant thereto shall comply with all
relevant provisions of law, including, without limitation, the Securities Act of
1933, as amended, the Exchange Act, the rules and regulations promulgated
thereunder, state securities laws, and the requirements of any stock exchange
upon which the Shares may then be listed, and shall be further subject to the
approval of counsel for the Company with respect to such compliance.

         As a condition to the exercise of an Option, the Company may require
the person exercising such Option to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares, if, in the
opinion of counsel for the Company, such a representation is required by any of
the aforementioned relevant provisions of law.

         Inability of the Company to obtain authority from any regulatory body
having jurisdiction, which authority is deemed by the Company's counsel to be
necessary to the lawful issuance and sale of any Shares hereunder, shall relieve
the Company of any liability in respect of the failure to issue or sell such
Shares as to which such requisite authority shall not have been obtained.

         14. RESERVATION OF SHARES. The Company, during the term of this
Plan, will at all times reserve and keep available such number of Shares as
shall be sufficient to satisfy the requirements of the Plan.

         15. OPTION AGREEMENT.  Options shall be evidenced by written
option agreements in such form as the Board shall approve.

         16. STOCKHOLDER APPROVAL.  The Plan shall be subject to approval by
the stockholders of the Company within twelve (12) months after the date the
Plan is adopted. Such stockholder approval shall be obtained in the degree and
manner required under applicable state and federal law and any stock exchange
rules.

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