**Exhibit31.2**

 

**CHIEFFINANCIAL OFFICER CERTIFICATION**

 

I, John B. Simmons, Vice President and Chief FinancialOfficer, certify that:

 

1. I have reviewed thisquarterly report on Form 10-Q of Stewart & Stevenson Services, Inc.;

 

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. The registrant’s othercertifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)and 15d-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 consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this quarterly report is being prepared;

 

b) evaluated theeffectiveness of the registrant’s disclosure controls and procedures andpresented in this quarterly report our conclusions about the effectiveness ofthe disclosure controls and procedures, as of the end of the period covered bythis quarterly report based on such evaluation; and

 

c) disclosed in thisquarterly report any change in the registrant’s internal control over financialreporting that occurred during the registrant’s most recent fiscal quarter thathas materially affected, or is reasonably likely to materially affect, theregistrant’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 the registrant’s auditors and theaudit committee of registrant’s board of directors (or persons performingequivalent 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:   May 25, 2004              |
|--------|---------------------------------------------|
|   |                                        |
|   |                                        |
|   | /s/  John B. Simmons                        |   |
|   | John  B. Simmons                            |
|   | Vice  President and Chief Financial Officer |
|   | (Principal  Financial Officer)              |

 

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