THRESHOLD PHARMACEUTICALS, INC.

POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes
and appoints Stephen B. Thau, the undersigned's true
and lawful attorney-in-fact to:

(1) execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer and/or director of
Threshold Pharmaceuticals, Inc., a Delaware corporation (the "Company"),
Forms 3, 4, and 5 in accordance with Section 16(a) of the
Securities Exchange Act of 1934 and the rules thereunder;

(2) do and perform any and all acts for and on behalf of
the undersigned which may be necessary or desirable to
complete and execute any such Form 3, 4, or 5, complete
and execute any amendment or amendments thereto, and timely
file such form with the United States Securities and
Exchange Commission and any stock exchange or
similar authority; and

(3) take any other action of any type whatsoever in connection
with the foregoing which, in the opinion of such attorney-in-fact,
may be of benefit to, in the best interest of, or legally
required by, the undersigned, it being understood that the
documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such
form and shall contain such terms and conditions as such
attorney-in-fact may approve in such attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full
power and authority to do and perform any and every act and thing
whatsoever requisite, necessary, or proper to be done in the
exercise of any of the rights and powers herein granted,
as fully to all intents and purposes as the undersigned might
or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming
all that such attorney-in-fact, or such attorney-in-fact's
substitute or substitutes, shall lawfully do or cause to be
done by virtue of this Power of Attorney and the rights and
powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the
request of the undersigned, are not assuming, nor is the
Company assuming, any of the undersigned's responsibilities
to comply with Section 16 of the Securities Exchange Act of 1934.

This Power of Attorney shall remain in full force and effect
until the undersigned is no longer required to file
Forms 3, 4, and 5 with respect to the undersigned's holdings
of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed
writing delivered to the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this
Power of Attorney to be executed as of this 25 day of January 2005.

/s/ George GC Parker
Signature

George GC Parker
Print Name