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                                                                    Exhibit 31.1

                      CHIEF EXECUTIVE OFFICER CERTIFICATION


I, Leonard S. Schwartz, Chairman, President and Chief Executive Officer of Aceto
Corporation, certify that:


       1. I have reviewed this Quarterly Report on Form 10-Q of Aceto
       Corporation (the "Registrant");

       2. Based on my knowledge, this Quarterly Report does not contain any
       untrue statement of a material fact or omit to state a material fact
       necessary to make the statements made, in light of the circumstances
       under which such statements were made, not misleading with respect to the
       period covered by this Quarterly Report;

       3. Based on my knowledge, the financial statements, and other financial
       information included in this Quarterly Report, fairly present in all
       material respects the financial condition, results of operations and cash
       flows of the Registrant as of, and for, the periods presented in this
       Quarterly Report;

       4. The Registrant's other certifying officer and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the Registrant
       and have:

       a) designed such disclosure controls and procedures, or caused such
       disclosure controls and procedures to be designed under our supervision,
       to ensure that material information relating to the Registrant, including
       its consolidated subsidiaries, is made known to us by others within those
       entities, particularly during the period in which this Quarterly Report
       is being prepared;

       b) evaluated the effectiveness of the Registrant's disclosure controls
       and procedures and presented in this Quarterly Report our conclusions
       about the effectiveness of the disclosure controls and procedures, as of
       the end of the period covered by this report based on such evaluation;
       and

       c) disclosed in this Quarterly Report any change in the Registrant's
       internal control over financial reporting that occurred during the
       Registrant's third fiscal quarter that has materially affected, or is
       reasonably likely to materially affect, the Registrant's internal control
       over financial reporting; and

       5. The Registrant's other certifying officer and I have disclosed, based
       on our most recent evaluation of internal control over financial
       reporting, to the Registrant's auditors and the audit committee of
       Registrant's board of directors (or persons performing the equivalent
       functions):

       a) all significant deficiencies and material weaknesses in the design or
       operation of internal control over financial reporting which are
       reasonably likely to adversely affect the Registrant's ability to record,
       process, summarize and report financial information; and

       b) any fraud, whether or not material, that involves management or other
       employees who have a significant role in the Registrant's internal
       control over financial reporting.

Dated: May 17, 2004

/s/  Leonard S. Schwartz
------------------------
 Chairman, President and Chief Executive Officer
(Principal Executive Officer)