**EXHIBIT31.1**

 

CERTIFICATIONOF CHIEF EXECUTIVE OFFICER

 

I, Thomas E. Noonan, Chief Executive Officerand President of Internet Security Systems, Inc., certify that:

 

1.     I have reviewed this annual report on Form10-K of Internet Security Systems, Inc. (the “Registrant”);

 

2.     Based on my knowledge, this annual reportdoes not contain any untruestatementof a material fact or omit to state a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading with respect to the period covered by thisannual report;

 

3.     Based on my knowledge, the financialstatements, and other financialinformation included in this annual report, fairly present in allmaterial respects the financialcondition, results of operations and cash flows of the Registrant as of, and for, the periodspresented in this annual report;

 

4.     Registrant’s other certifying officer and Iam responsible forestablishingand 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 15(d)-15(f)for the Registrant and have:

 

a.     designed such disclosurecontrols and procedures, or caused such disclosure controls and procedures tobe designed under our supervision, to ensure that material information relatingto the Registrant, including its consolidated subsidiaries, is made known to usby others within those entities, particularly during the period in which thisannual report is being prepared;

 

b.     designed such internalcontrol over financial reporting, or caused such internal control overfinancial reporting to be designed under oursupervision, to provide reasonable assuranceregarding the reliability of financial reporting and the preparation offinancial statements for external purposes in accordance with generallyaccepted accounting principles;

 

c.     evaluated the effectivenessof the Registrant’s disclosure controls and procedures and presented in thisannual report our conclusions about the effectiveness of the disclosurecontrols and procedures, as of the end of the period covered by this annualreport based on such evaluation; and

 

d.     disclosed in this annualreport any change in the Registrant’s internal control over financial reportingthat occurred during Registrant’s fourth quarter of fiscal 2005 that hasmaterially affected, or is reasonably likely to materially affect, theRegistrant’s internal control over financial reporting; and

 

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

 

a.     all significant deficienciesand material weaknesses in the design or operation of internal control overfinancial reporting which are reasonably likely to adversely affect theRegistrant’s ability to record, process, summarize and report financialinformation; and

 

b.     any fraud, whether or notmaterial, that involves management or other employees who have a significantrole in Registrant’s internal control over financial reporting.

 
|          | /s/  THOMAS E. NOONAN                  |   |
|---------------|----------------------------------------|--------|
|          | Thomas E. Noonan                       |
|          | Chief Executive Officer and  President |
|          |                                   |
| March 6, 2006 |                                   |

 

----