**Exhibit 31.1**

 

**CERTIFICATIONOF PRINCIPAL EXECUTIVE OFFICERSection 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 suchdisclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidated subsidiary,is made known to us by others within those entities, particularly during theperiod in which this report is being prepared; 

 

b)             evaluated theeffectiveness of the registrant’s disclosure controls and procedures andpresented in this report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by thisreport based on such evaluation; 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 significantdeficiencies and material weaknesses in the design or operation of internalcontrol over financial reporting which are reasonably likely to adverselyaffect the registrant’s ability to record, process, summarize and reportfinancial information; and 

 

b)             any fraud, whether ornot material, that involves management or other employees who have asignificant role in the registrant’s internal control over financial reporting.

 
| Date: November 13, 2003               |
|---------------------------------------|
|                                  |
| /s/ Anthony R. Fabiano                |   |
| Anthony R. Fabiano                    |   |
| President and Chief Executive Officer |   |

 

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