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                                                                     EXHIBIT 5.1



                       [LETTERHEAD OF COOLEY GODWARD LLP]



May 31, 2001



eBay Inc.
2145 Hamilton Avenue
San Jose, California 95125

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by eBay Inc. (the "Company") of a Registration Statement on Form
S-4 (the "Registration Statement") with the Securities and Exchange Commission
(the "Commission") covering registration of 10,000,000 shares of the Company's
Common Stock.

In connection with this opinion, we have examined the Registration Statement,
the Company's Certificate of Incorporation and Bylaws, each as amended and such
other documents, records, certificates, memoranda and other instruments as we
deem necessary as a basis for this opinion. We have assumed the genuineness and
authenticity of all documents submitted to us as originals, the conformity to
originals of all documents submitted to us as copies thereof, and the due
execution and delivery of all documents where due execution and delivery are a
prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the shares of Common Stock to be issued by the Company have been duly
authorized and, when issued and sold by the Company in the manner described in
the Registration Statement and in accordance with the resolutions adopted by the
Board of Directors of the Company, will be legally issued, fully paid and
nonassessable.

We consent to the reference to our firm under the caption "Legal Matters" in the
Prospectus included in the Registration Statement and to the filing of this
opinion as an exhibit to the Registration Statement.

Very truly yours,

COOLEY GODWARD LLP



By: /s/ Michael J. Sullivan
   --------------------------------
   Michael J. Sullivan