**EXHIBIT 31.1**

 

CERTIFICATION OFCHIEF EXECUTIVE OFFICER

 

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

 

1. I have reviewed thisquarterly report on Form 10-Q of Internet Security Systems, Inc. (the“Registrant”);

 

2. Based on my knowledge,this quarterly 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 quarterly report; 

 

3. Based on my knowledge,the financial statements, and other financial information included in thisquarterly report, fairly present in all material respects the financialcondition, results of operations and cash flows of the Registrant as of, andfor, the periods presented in this quarterly report; 

 

4. Registrant’s othercertifying officer and I am responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-15(f) for the Registrantand have: 

 

a.designed such disclosure controls and procedures, or caused such disclosurecontrols and procedures to be designed under our supervision, to ensure thatmaterial information relating to the Registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this quarterly report is being prepared;

 

b.designed such internal control over financial reporting, or caused suchinternal control over financial reporting to be designed under our supervision,to provide reasonable assurance regarding the reliability of financialreporting and the preparation of financial statements for external purposes inaccordance with generally accepted accounting principles;

 

c.evaluated the effectiveness of the Registrant’s disclosure controls andprocedures and presented in this quarterly report our conclusions about theeffectiveness of the disclosure controls and procedures, as of the end of theperiod covered by this quarterly report based on such evaluation; and

 

d.disclosed in this quarterly report any change in the Registrant’s internalcontrol over financial reporting that occurred during Registrant’s secondquarter of fiscal 2005 that has materially affected, or is reasonably likely tomaterially affect, the Registrant’s internal control over financial reporting;and

 

5. The Registrant’s othercertifying officer and I have disclosed, based on our most recent evaluation ofinternal control over financial reporting, to Registrant’s auditors and theaudit committee of the Registrant’s board of directors (or persons performingthe equivalent functions):

 

a. allsignificant deficiencies and material weaknesses in the design or operation ofinternal control over financial reporting which are reasonably likely toadversely affect the Registrant’s ability to record,

 

----

 

process, summarize andreport financial information; and

 

b. anyfraud, whether or not material, that involves management or other employees whohave a significant role in Registrant’s internal control over financialreporting.

 
|                | /s/ THOMAS E. NOONAN                   |   |
|---------------------|----------------------------------------|--------|
|                | Thomas E. Noonan                       |
|                | Chief Executive Officer  and President |
|                |                                   |
| August 9, 2005 |                                   |

 

----