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                          [COOLEY GODWARD LETTERHEAD]

                                                                     EXHIBIT 5.1

April 29, 1998

First Virtual Corporation
3393 Octavius Drive, Suite 102
Santa Clara, CA 95054

Ladies and Gentlemen:

You have requested our opinion with respect to certain matters in connection
with the filing by First Virtual Corporation (the "Company"), of a Registration
Statement on Form S-1, as amended (the "Registration Statement") with the
Securities and Exchange Commission (the "Commission"), covering the
underwritten public offering of up to an aggregate of 3,312,000 shares of the
Company's common stock  (the "Common Stock") (including 432,000 shares of
Common Stock for which the underwriters will be granted an over-allotment
option), 3,132,000 of which are being sold by the Company (the "Company
Shares") and 180,000 of which are being sold by certain stockholders of the
Company (the "Selling Stockholder Shares").

In connection with this opinion, we have (i) examined and relied upon the
Registration Statement and related prospectus included therein (the
"Prospectus"), the Company's Certificate of Incorporation and Bylaws, and the
originals or copies certified to our satisfaction of such records, documents,   
certificates, memoranda and other instruments as in our judgment are necessary
or appropriate to enable us to render the opinion expressed below, (ii) assumed
that the Amended and Restated Certificate of Incorporation, as set forth in
Exhibit 3.3 of the Registration Statement, shall have been duly approved and
filed with the office of the Delaware Secretary of State, and (iii) assumed
that the shares of the Common Stock will be sold by the underwriters at a price
established by the Pricing Committee of the Board of Directors of the Company.

On the basis of the foregoing, and in reliance thereon, we are of the opinion
that the Company Shares and the Selling Stockholder Shares, when sold, issued
and paid for in accordance with the Registration Statement and related
Prospectus, will be validly 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/ Lee F. Benton
   -------------------------
    Lee F. Benton