Exhibit 32.1


                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350
                               ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

        In connection with the Quarterly Report of Aceto Corporation, a New York
corporation (the "Company"), on Form 10-Q for the period ended March 31, 2005 as
filed with the Securities and Exchange Commission on the date hereof (the
"Report"), I, Leonard S. Schwartz, Chairman, President and Chief Executive
Officer of the Company, certify, pursuant to Section 18 U.S.C. 1350, as adopted
pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

        (1) The Report fully complies with the requirements of Section 13(a) and
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/ Leonard S. Schwartz
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Leonard S. Schwartz
Chairman, President and
Chief Executive Officer
May 6, 2005