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                                                                   EXHIBIT 10.31

                          PLEDGE AND SECURITY AGREEMENT


        This Pledge and Security Agreement (the "Agreement") is entered into
this 23rd day of November by and between Pets.com, Inc., a California
corporation (the "Company") and Paul Manca ("Purchaser").

                                    RECITALS

        In connection with Purchaser's exercise of an option to purchase certain
shares of the Company's Common Stock (the "Shares") pursuant to an Option
Agreement dated September 8, 1999 between Purchaser and the Company, Purchaser
is delivering a promissory note dated November 23, 1999 herewith (the "Note") in
full or partial payment of the exercise price for the Shares. The company
requires that the Note be secured by a pledge of the Shares on the terms set
forth below.

                                    AGREEMENT

        In consideration of the Company's acceptance of the Note as full or
partial payment of the exercise price of the Shares, and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the parties
hereto agree as follows:

        1. The Note shall become payable in full upon the voluntary or
involuntary termination or cessation of employment of Purchaser with the
Company, for any reason, with or without cause (including death or disability).

        2. Purchaser shall deliver to the Secretary of the Company, or his or
her designee (hereinafter referred to as the "Pledge Holder"), all certificates
representing the Shares, together with an Assignment Separate from Certificate
in the form attached to this Agreement as Attachment A executed by Purchaser and
by Purchaser's spouse (if required for transfer), in blank, for use in
transferring all or a portion of the Shares to the Company if, as and when
required pursuant to this Agreement. In addition, if Purchaser is married,
Purchaser's spouse shall execute the signature page attached to this Agreement.

        3. As security for the payment of the Note and any renewal, extension or
modification of the Note, Purchaser hereby grants to the Company a security
interest in and pledges with and delivers to the Company Purchaser's Shares
(sometimes referred to herein as the "Collateral").

        4. In the event that Purchaser prepays all or a portion of the Note, in
accordance with the provisions thereof, Purchaser intends, unless written notice
to the contrary is delivered to the Pledge Holder, that the Shares represented
by the portion of the Note so repaid, including annual interest thereon, shall
continue to be so held by the Pledge Holder, to serve as independent collateral
for the outstanding portion of the Note for the purpose of



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commencing the holding period set forth in Rule 144(d) promulgated under the
Securities Act of 1933, as amended (the "Securities Act").

        5. In the event of any foreclosure of the security interest created by
this Agreement, the Company may sell the Shares at a private sale or may
repurchase the Shares itself. The parties agree that, prior to the establishment
of a public market for the Shares of the Company, the securities laws affecting
sale of the Shares make a public sale of the Shares commercially unreasonable.
The parties further agree that the repurchasing of such Shares by the Company,
or by any person to whom the Company may have assigned its rights under this
Agreement, is commercially reasonable if made at a price determined by the Board
of Directors in its discretion, fairly exercised, representing what would be the
fair market value of the Shares reduced by any limitation on transferability,
whether due to the size of the block of shares or the restrictions of applicable
securities laws.

        6. In the event of default in payment when due of any indebtedness under
the Note, the Company may elect then, or at any time thereafter, to exercise all
rights available to a secured party under the California Commercial Code
including the right to sell the Collateral at a private or public sale or
repurchase the Shares as provided above. The proceeds of any sale shall be
applied in the following order:

               (a) To the extent necessary, proceeds shall be used to pay all
reasonable expenses of the Company in enforcing this Agreement and the Note,
including, without limitation, reasonable attorney's fees and legal expenses
incurred by the Company.

               (b) To the extent necessary, proceeds shall be used to satisfy
any remaining indebtedness under Purchaser's Note.

               (c) Any remaining proceeds shall be delivered to Purchaser.

        7. Upon full payment by Purchaser of all amounts due under the Note,
Pledge Holder shall deliver to Purchaser all Shares in Pledge Holder's
possession belonging to Purchaser, and Pledge Holder shall thereupon be
discharged of all further obligations under this Agreement.


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        The parties have executed this Pledge and Security Agreement as of the
date first set forth above.

                                    COMPANY:

                                    PETS.COM, INC.


                                    By: /s/ Julie Wainwright
                                       -----------------------------------------
                                    Name: Julie Wainwright
                                         ---------------------------------------
                                               (print)

                                    Title: Chief Executive Officer
                                          --------------------------------------

                                    435 Brannan Street, Suite 100
                                    San Francisco, CA  94107

                                    PURCHASER:

                                    PAUL MANCA

                                    /s/ Paul Manca
                                    --------------------------------------------
                                    (Signature)

                                    Paul Manca
                                    --------------------------------------------
                                                 (Print Name)

                                    Address:

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

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


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                                 PROMISSORY NOTE


$187,500                                               San Francisco, California
                                                               November 23, 1999


        For value received, the undersigned promises to pay Pets.com, Inc., a
California corporation (the "Company"), at its principal office the principal
sum of $187,500 with interest from the date hereof at a rate of 6.08% per annum,
compounded annually, on the unpaid balance of such principal sum. Such principal
and interest shall be due and payable on November 23, 2003.

        If the undersigned's employment or consulting relationship with the
Company is terminated prior to payment in full of this Note, this Note shall be
immediately due and payable.

        Principal and interest are payable in lawful money of the United States
of America. AMOUNTS DUE UNDER THIS NOTE MAY BE PREPAID AT ANY TIME WITHOUT
PREMIUM OR PENALTY.

        Should suit be commenced to collect any sums due under this Note, such
sum as the Court may deem reasonable shall be added hereto as attorneys' fees.
The makers and endorsers have severally waived presentment for payment, protest,
notice of protest and notice of nonpayment of this Note.

        This Note, which is full recourse, is secured by a pledge of certain
shares of Common Stock of the Company and is subject to the terms of a Pledge
and Security Agreement between the undersigned and the Company of even date
herewith.



                                                   /s/ Paul Manca
                                                   -----------------------------
                                                   Paul Manca