EXHIBIT 32.2

         CERTIFICATION OF CHIEF FINANCIAL OFFICER PURSUANT TO 18 U.S.C.
             SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE
                           SARBANES-OXLEY ACT OF 2002

      In connection with the Quarterly Report on Form 10-Q of Hybridon, Inc.
(the "Company") for the period ended March 31, 2005 as filed with the Securities
and Exchange Commission on the date hereof (the "Report"), the undersigned,
Robert G. Andersen, Chief Financial Officer of the Company, hereby certifies,
pursuant to 18 U.S.C. Section 1350, that:

            (1) the Report fully complies with the requirements of Section 13(a)
      or 15(d) of the Securities Exchange Act of 1934; and

            (2) the information contained in the Report fairly presents, in all
      material respects, the financial condition and results of operations of
      the Company.

      A signed original of this written statement has been provided to Hybridon,
Inc. and will be retained by Hybridon, Inc. and furnished to the Securities and
Exchange Commission or its staff upon request.

                                              /s/ ROBERT G. ANDERSEN
                                              -------------------------------
                                                  Robert G. Andersen
                                               Chief Financial Officer

Date: May 10, 2005