                                                                     Exhibit 5.1

                      SWIDLER BERLIN SHEREFF FRIEDMAN, LLP

                          THE CHRYSLER BUILDING
                          405 LEXINGTON AVENUE
                            NEW YORK, NY 10174            THE WASHINGTON HARBOUR
                         TELEPHONE (212) 973-0111    3000 K STREET,NW, SUITE 300
                         FACSIMILE (212) 891-9598      WASHINGTON, DC 20007-5116
                           WWW.SWIDLAW.COM              TELEPHONE (202) 424-7500
                                                        FACSIMILE (202) 424-7647

                                  July 29, 2004

Bluefly, Inc.
42 West 39th Street
New York, New York 10018

Ladies and Gentlemen:

        On the date hereof, Bluefly, Inc., a Delaware corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") a Post-Effective Amendment No. 5 to the Registration Statement on
Form S-8 that it filed with the Commission on April 12, 1999 (as amended, the
"Registration Statement"), relating to 2,000,000 additional shares (the
"Shares") of the Company's common stock, par value $0.01 per share, which are
being offered pursuant to the Company's 1997 Stock Option Plan (the "Plan").
This opinion is an exhibit to the Registration Statement.

        We have at times acted as special counsel to the Company in connection
with certain corporate and securities matters, and in such capacity we are
familiar with the various corporate and other proceedings relating to the
proposed offer and sale of the Shares as contemplated by the Registration
Statement.

        In connection with this opinion, we have examined and are familiar with
originals or copies, certified or otherwise identified to our satisfaction, of
(i) the Company's Certificate of Incorporation as presently in effect, (ii) the
Company's By-Laws as presently in effect, (iii) minutes and other instruments
evidencing actions taken by the Company's directors and stockholders, (iv) the
Plan and (v) a form of option agreement, which we understand is typically used
by the Company in connection with grants under the Plan. In our examination of
all such agreements, documents, certificates and instruments, we have assumed
the genuineness of all signatures, the authenticity of all agreements,
documents, certificates and instruments submitted to us as originals and the
conformity with the originals of all agreements, documents, certificates and
instruments submitted to us as certified, conformed or photostatic copies.
Insofar as this opinion relates to securities to be issued in the future, we
have assumed that all applicable laws, rules and regulations in effect at the
time of such issuance will be the same as such laws, rules and regulations in
effect as of the date hereof.

<PAGE>

        Our opinion herein is based solely upon the General Corporation Law of
the State of Delaware, and we express no opinion with respect to any other laws
(including, without limitation, the application of the securities or "Blue Sky"
laws of any state to the offer and/or sale of the Shares).

        Based on the foregoing, and subject to and in reliance upon the accuracy
and completeness of the information relevant thereto provided to us, it is our
opinion that the Shares have been duly authorized, and (subject to the
effectiveness of the Registration Statement and compliance with applicable state
laws (including securities laws) of the states in which the Shares may be
offered and sold), when issued in accordance with the terms of the Plan and any
applicable option agreement for options issued thereunder, will be legally and
validly issued, fully paid and non-assessable.

        We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and as an exhibit to any filing made by the Company under
the securities or other laws of any state of the United States in which the
Shares may be offered and sold. In giving such consent, we do not thereby admit
that we are in the category of persons whose consent is required under Section 7
of the Act of 1933, or the rules and regulations of the Commission thereunder.

        This opinion is furnished to you in connection with the filing of the
Registration Statement, and is not to be used, circulated, quoted or otherwise
relied upon for any other purpose, except as expressly provided in the preceding
paragraph, without our express written consent. This opinion is rendered to you
as of the date hereof, and we undertake no obligation to advise you of any
change in any applicable law or in facts or circumstances which might affect any
matters or opinions set forth herein.

                                        Very truly yours,

                                        /s/ Swidler Berlin Shereff Friedman, LLP

                                        Swidler Berlin Shereff Friedman, LLP

