**Exhibit 31.1**

 

**CERTIFICATIONOF PRINCIPAL EXECUTIVE OFFICER**

** **

**Section 302 Certification**

 

I, Anthony R. Fabiano, certify that:

 

1.               I have reviewed this quarterly report onForm 10-Q of American Science and Engineering, Inc.;

 

2.               Based on myknowledge, this report does not contain any untrue statement of a material factor omit to state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report; 

 

3.               Based on my knowledge, the financialstatements, and other financial information included in this report, fairlypresent in all material respects the financial condition, results of operationsand cash flows of the registrant as of, and for, the periods presented in thisreport; 

 

4.               The registrant’s other certifyingofficer and I are responsible for establishing and maintaining disclosurecontrols and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) for the registrant and we have: 

 

a)              designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designedunder our supervision, to ensure that material information relating to theregistrant, including its consolidated subsidiary, is made known to us byothers within those entities, particularly during the period in which thisreport is being prepared; 

 

b)             evaluated the effectiveness of theregistrant’s disclosure controls and procedures and presented in this reportour conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and 

 

c)              disclosed in this report any change inthe registrant’s internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f)) that occurred during theregistrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarterin the case of an annual report) that has materially affected, or is reasonablylikely to materially affect, the registrant’s internal control over financialreporting. 

 

5.               The registrant’s other certifyingofficer and I have disclosed, based on our most recent evaluation of internalcontrol over financial reporting, to the registrant’s auditors and the auditcommittee of the registrant’s board of directors (or persons performing theequivalent functions): 

 

a)              all significant deficiencies and materialweaknesses in the design or operation of internal control over financialreporting which are reasonably likely to adversely affect the registrant’sability to record, process, summarize and report financial information; and 

 

b)             any fraud, whether or not material, thatinvolves management or other employees who have a significant role in theregistrant’s internal control over financial reporting. 

 
| Date: February 23, 2004               |   |
|---------------------------------------|--------|
|                                  |   |
|  /s/ Anthony R. Fabiano          |   |   |
| Anthony R. Fabiano                    |   |
| President and Chief Executive Officer |   |
|                                       |        |  |

 

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