Exhibit 99.1

                            CERTIFICATION 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 Annual Report of Neose Technologies, Inc. (the "Company")
on Form 10-K for the period ending December 31, 2002 as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, C. Boyd
Clarke, President and Chief Executive Officer of the Company, certify, pursuant
to 18 U.S.C. (S) 1350, as adopted pursuant to (S) 906 of the Sarbanes-Oxley Act
of 2002, 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.


/s/ C. Boyd Clarke

C. Boyd Clarke
President and Chief Executive Officer

March 17, 2003