EXHIBIT 5.1

                        GERSTEN, SAVAGE & KAPLOWITZ, LLP
                              101 East 52nd Street
                          New York, New York 10022-6018


                                              November 3, 2000


ACTV, Inc.
1270 Avenue of the Americas
New York, New York 10020

      Re:   ACTV, Inc. Registration Statement on Form S-3
            Registration No. 333-

Ladies and Gentlemen:

      In connection with the referenced Registration Statement on Form S-3 (the
"Registration Statement"), filed with the Securities and Exchange Commission
under the Securities Act of 1933, as amended (the "Act"), and the rules and
regulations under the Act (the "Rules"), we have been requested by ACTV, Inc., a
Delaware corporation (the "Company"), to furnish our opinion as to the legality
of the offering of 1,548,925 shares (the "Selling Security Holders' Shares") of
the Company's common stock, par value $0.10 per share (the "Common Stock"). The
Selling Security Holders" Shares may be sold by security holders who have
previously acquired such shares of Common Stock from the Company.

      In connection with the furnishing of this opinion, we have reviewed such
records and documents and made such examination of law as we may have deemed
relevant. We also have examined and relied upon representations as to factual
matters contained in certificates of officers of the Company, and have made
those other investigations of fact and law and have examined and relied upon the
originals, or copies certified or otherwise identified to our satisfaction, of
those documents, records, certificates or other instruments, and upon factual
information otherwise supplied to us, as in our judgment are necessary or
appropriate to render the opinions expressed below.

      In addition, we have assumed, without independent investigation, the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity of original documents to all documents submitted to
us as certified, photostatic, reproduced or conformed copies, the authenticity
of all the latter documents and the legal capacity of all individuals who have
executed any of the documents reviewed by us.

      Based upon the foregoing, we are of the opinion that (i) the Selling
Security Holders" Shares are duly authorized and when issued, delivered and paid
for as contemplated in the Registration Statement, will be validly issued, fully
paid and nonassessable.

      Our opinions expressed above are limited to the General Corporation Law of
the State of Delaware. Please be advised that no member of this firm is admitted
to practice in the State of Delaware. Our opinion is rendered only with respect
to laws and the rules, regulations and orders under them, which are currently in
effect.



      We hereby consent to the use of this opinion as an Exhibit to the
Registration Statement and to the use of our name under the heading "Legal
Matters" contained in the prospectus included in the Registration Statement. In
giving this consent, we do not admit that we come within the category of persons
whose consent is required by the Act or the Rules.

                                       Very truly yours,


                                       GERSTEN, SAVAGE & KAPLOWITZ, LLP