EXHIBIT 5.1

                                December 3, 1998


XOOM.com, Inc.
300 Montgomery Street
3rd Floor
San Francisco, CA 94104


Ladies and Gentlemen:

     At your request, we have examined the Registration Statement on Form S-1 of
XOOM.com, Inc., a Delaware corporation (the "Company"), filed with the
Securities and Exchange Commission (the "Registration Statement") on August 28,
1998, relating to the registration under the Securities Act of 1933, as amended,
of up to 3,450,000 shares of the Company's common stock, $.0001 par value (the
"Stock"), all of which are authorized but unissued stock to be offered and sold
by the Company (including up to 450,000 shares subject to the underwriters'
over-allotment option).  The Stock is to be sold to the underwriters named in
the Registration Statement for resale to the public.

     As counsel to the Company, we have examined the proceedings taken by the
Company in connection with the issuance and sale by the Company of up to
3,450,000 shares of Stock.

     We are of the opinion that the shares of Stock to be offered and sold 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 use of this opinion as an exhibit to the Registration
Statement and further consent to all references to us in the Registration
Statement, the prospectus constituting a part thereof and any amendments
thereto.

                              Very truly yours,

                              /s/ Morrison & Foerster LLP