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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 second 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.

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Dated: February 12, 2004


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