As filed with the Securities and Exchange Commission on April 22, 2004
                                   Registration No. 333- SEC File No 333-102513
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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                              --------------------

                        POST-EFFECTIVE AMENDMENT NO. 1 TO
                                    FORM S-3
                                   ON FORM S-1
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                              --------------------

                           HEMISPHERX BIOPHARMA, INC.
             (Exact name of registrant as specified in its charter)

                                    Delaware
         (State or other jurisdiction of incorporation or organization)

                                   52-0845822
                      (I.R.S. Employer Identification No.)
                              --------------------

                               1617 JFK Boulevard
                        Philadelphia, Pennsylvania 19103
                                 (215) 988-0080

       (Address, including zip code, and telephone number, including area
               code, of registrant's principal executive offices)
                                       --
                William A. Carter, M.D., Chief Executive Officer
                           Hemispherx Biopharma, Inc.
                               1617 JFK Boulevard
                        Philadelphia, Pennsylvania 19103
                                 (215) 988-0080

 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                        Copies of all communications to:
                              Richard Feiner, Esq.
                        Silverman Sclar Shin & Byrne PLLC
                        381 Park Avenue South, Suite 1601
                            New York, New York, 10016
                                 (212) 779-8600
                               Fax (212) 779-8600









         Approximate date of proposed sale to the public:  Not Applicable.

         If the only securities  being registered on this form are being offered
pursuant to dividend or interest  reinvestment plans, please check the following
box. [ ]

         If any of the  securities  being  registered  on  this  Form  are to be
offered  on a  delayed  or  continuous  basis  pursuant  to Rule 415  under  the
Securities Act of 1933 ("Securities Act"), other than securities offered only in
connection with dividend or reinvestment plans, check the following box. [ ]

         If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list  the  Securities  Act  registration  statement  number  of the  earlier
effective registration statement for the same offering. [ ]

         If this form is a  post-effective  amendment  filed  pursuant to 462(c)
under the  Securities  Act,  check the following box and list the Securities Act
registration number of the earlier effective registration statement for the same
offering.[ ]

         If delivery of the  prospectus  is expected to be made pursuant to Rule
434, please check the following box. [ ]

The  registrant  hereby  deregisters  all of the  securities  of the  registrant
previously registered in the original  Registration  Statement on Form S-3 filed
with the Commission on January 14, 2003. These  securities  consisted of 499,996
warrants  to purchase  shares of our common  stock and  5,499,996  shares of our
common stock. No securities were sold pursuant to the Registration Statement.

The  registrant is using Form S-1 because it does not currently  meet all of the
requirements for use of Form S-3.






                                   SIGNATURES

Pursuant to the  requirement  of the  Securities Act of 1933, the Registrant has
duly caused this Post-Effective Amendment No. 1 to its Registration Statement to
be signed on its behalf by the  undersigned,  thereunto  duly  authorized in the
City of Philadelphia,  Commonwealth of  Pennsylvania,  on the 22th day of April,
2004.

                                                     HEMISPHERX BIOPHARMA, INC.
                                                    (Registrant)

                                             By:     /s/ William A. Carter
                                                     ----------------------
                                                     William A. Carter, M.D.,
                                                     Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this  Post-Effective
Amendment No. 1 to the  Registration  Statement has been signed by the following
persons in the capacities indicated on the dates indicated.

Signature                      Title                         Date
---------                      --------                      ---------------

/s/ William A. Carter          Chairman of the Board,        April 22, 2004
---------------------          Chief Executive Officer
William A. Carter, M.D.        (Principal Executive) and Director

Richard Piani*                 Director                      April 22, 2004

Robert E. Peterson*            Chief Financial Officer and   April 22, 2004
                               Chief Accounting Officer

Ransom Etheridge*              Secretary And Director        April 22, 2004

William Mitchell, M.D., Ph.D.* Director                      April 22, 2004

Iraj-Eqhbal Kiani, M.D.        Director


*  By:   /s/ Wlliam A. Carter
         --------------------
         William A. Carter, M.D.,
         Attorney-in-Fact