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                                                                    EXHIBIT 5.1

                               September 25, 2001

E-Stamp Corporation
2051 Stierlin Court
Mountain View, California  94043

      Re: REGISTRATION STATEMENT ON FORM S-8
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Ladies and Gentlemen:

          We have examined the Registration Statement on Form S-8 (the
"Registration Statement") to be filed by you with the Securities and Exchange
Commission on or about September 25, 2001 (the "Registration Statement") in
connection with the registration under the Securities Act of 1933, as amended
(the "Securities Act"), of 7,000,000 shares of your Common Stock reserved for
issuance under your 1999 Stock Plan (the "Plan"). As your legal counsel, we have
examined the proceedings taken and are familiar with the proceedings proposed to
be taken by you in connection with the sale and issuance of the Common Stock
under the Plan.

          It is our opinion that, when issued and sold in the manner referred
to in the Plan and pursuant to the agreements which accompany the Plan, the
Common Stock issued and sold thereby will be legally and validly issued, fully
paid and nonassessable.

          We consent to the use of this opinion as an exhibit to the
Registration Statement and further consent to the use of our name wherever
appearing in the Registration Statement, including any Prospectuses constituting
a part thereof, and any amendments thereto.

                                            Very truly yours,

                                            /s/ Wilson Sonini Goodrich & Rosati

                                            WILSON SONSINI GOODRICH & ROSATI
                                            Professional Corporation