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**CERTIFICATION**

|   | 1.       | I                  have reviewed this quarterly report on Form 10-Q of Aceto Corporation                  (the “Registrant”);                                                                                                                                                                                                                                                                                                                                          |
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|   | 2.       | Based on my knowledge,                  this 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 report;                                      |
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|   | 3.       | Based on my knowledge,                  the                  financial statements, and other financial information included                  in this                  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 report;                                                                          |
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|   | 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)) and internal control over financial reporting (as                  defined                  in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the Registrant                  and                  have: |
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|   |     | 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 report is being prepared; |
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|   |     | b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | designed such internal control over                  financial                  reporting, or caused such internal control over financial reporting                  to be                  designed under our supervision, to provide reasonable assurance                  regarding                  the reliability of financial reporting and the preparation of financial                  statements for external purposes in accordance with U.S. generally                  accepted accounting principles; and |
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|   |     | c)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | evaluated the effectiveness of the                  Registrant’s disclosure controls and procedures and presented in this                  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 |
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|   |     | d)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | disclosed in this report any change                  in the                  Registrant’s internal control over financial reporting that occurred                  during the Registrant’s most recent quarter (the registrant’s fourth                  fiscal quarter in the case of an annual report) that has materially                  affected, or is reasonably likely to materially affect, the Registrant’s                  internal control over financial reporting; and |
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|   | 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 the Registrant’s board of directors (or persons                  performing the equivalent functions):                                                                                  |
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|   |     | 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 |
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|   |     | 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:   November                    9, 2007 |
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| /s/   Leonard                      S. Schwartz              |   |
| Chairman,                      President and Chief Executive Officer  |
| (Principal                      Executive Officer)                         |   |