EXHIBIT 5.01


                                 April 11, 2001



Hybrid Networks, Inc.
6409 Guadalupe Mines Road
San Jose, California  95120

Ladies and Gentlemen:

     At your request, we have examined the Registration Statement on Form S-3
(the "Registration Statement") to be filed by you with the Securities and
Exchange Commission (the "Commission") on or about April 11, 2001 in connection
with the registration under the Securities Act of 1933, as amended, of an
aggregate of 4,484,103 shares of your common stock (the "Stock"), which shares
either will be, issued and outstanding as of the date on which the Registration
Statement is declared effective by the Securities and Exchange Commission or
will be issuable upon exercise of the Warrants (as defined below) held by
Halifax Fund, L.P. (the "Selling Stockholder"). All of the Stock will be sold by
the Selling Stockholder.

     In rendering this opinion, we have examined the following.

     (1)  your Amended and Restated Certificate of Incorporation, certified by
          the Delaware Secretary of State on February 9, 2001, and your
          Certificate of Designation of Series J Non-Convertible Preferred
          Stock, certified by the Delaware Secretary of State on February 9,
          2001;

     (2)  your Bylaws, certified by your Secretary on March 22, 2001;

     (3)  the Registration Statement, together with the Exhibits filed as a part
          thereof or incorporated therein by reference, including the 6%
          Convertible Debenture Due 2003, dated February 16, 2001, between the
          Company and the Selling Stockholder (the "Debenture"), the Common
          Stock Purchase Warrant, dated February 16, 2001 between the Company
          and the Selling Stockholder and the Adjustment Warrant, dated February
          16, 2001, between the Company and the Selling Stockholder
          (collectively, the "Warrants");

     (4)  the Prospectus prepared in connection with the Registration Statement;

     (5)  the minutes of meetings and actions by written consent of the
          stockholders and Board of Directors that are contained in your minute
          books;

     (6)  a certificate that you provided to us from your transfer agent of even
          date herewith verifying the number of your issued and outstanding
          shares of capital stock as of the date hereof and a list that you
          prepared of options and warrants respecting your capital stock and of
          any rights to purchase capital stock dated March 27, 2001, verifying
          the number of such issued and outstanding securities (the "Stock
          Records");

     (7)  the Securities Purchase Agreement between the Selling Stockholder and
          the Company dated as of February 16, 2001; and

     (8)  a Management Certificate addressed to us and dated of even date
          herewith executed by you containing certain factual and other
          representations (the "Management Certificate").

     In our examination of documents for purposes of this opinion, we have
assumed, and express no opinion as






to, the genuineness of all signatures on original documents, the authenticity
and completeness of all documents submitted to us as originals, the conformity
to originals and completeness of all documents submitted to us as copies, the
legal capacity of all persons or entities executing the same, the lack of any
undisclosed termination, modification, waiver or amendment to any document
reviewed by us and the due authorization, execution and delivery of all
documents where due authorization, execution and delivery are prerequisites to
the effectiveness thereof. We have also assumed that the certificates
representing the Stock, when issued, will be properly signed by your authorized
officers or their agents.

     As to matters of fact relevant to this opinion, we have relied solely upon
our examination of the documents referred to above and have assumed the current
accuracy and completeness of the information obtained from the documents
referred to above and the representations and warranties made by your
representatives to us, including but not limited to those set forth in the
Management Certificate. We have made no independent investigation or other
attempt to verify the accuracy of any of such information or to determine the
existence or non-existence of any other factual matters; however, we are not
aware of any facts that would cause us to believe that the opinion expressed
herein is not accurate.

     We are admitted to practice law in the State of California, and we render
this opinion only with respect to, and express no opinion herein concerning the
application or effect of the laws of any jurisdiction other than, the existing
laws of the United States of America, of the State of California and, with
respect to the validity of corporate action and the requirements for the
issuance of stock, of the State of Delaware.

     In connection with our opinion expressed below, we have assumed that, at or
prior to the time of the delivery of any shares of Stock, the Registration
Statement will have been declared effective under the Securities Act of 1933, as
amended, that the registration will apply to such shares of Stock and will not
have been modified or rescinded and that there will not have occurred any change
in law affecting the validity or enforceability of such shares of Stock.

     Based upon the foregoing, it is our opinion that the aggregate of up to
4,484,103 shares of Stock to be sold by the Selling Stockholder pursuant to the
Registration Statement, including the shares to be outstanding as of the date on
which the Registration Statement is declared effective by the Securities and
Exchange Commission and the shares issuable upon exercise of the Warrants, when
issued, sold and delivered in the manner and for the consideration stated in the
Registration Statement and Prospectus, and in accordance with the terms of the
Debenture and Warrants, as the case may be, will be 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 all references to us, if any, in the
Registration Statement, the Prospectus constituting a part thereof and any
amendments thereto. This opinion speaks only as of its date and we assume no
obligation to update this opinion should circumstances change after the date
hereof. This opinion is intended solely for use in connection with the sale of
shares subject to the Registration Statement and is not to be relied upon for
any other purpose.

                                          Very truly yours,

                                          /s/ Fenwick & West LLP

                                          FENWICK & WEST LLP