**Exhibit 31.2**

 

**CHIEFFINANCIAL OFFICER CERTIFICATION**

 

I, JohnB. Simmons, Vice President and Chief Financial Officer, certify that:

 

1. I have reviewed this quarterly report on Form 10-Qof Stewart & Stevenson Services, Inc.;

 

2. Based on my knowledge, this quarterly report doesnot contain any untrue statement of a material fact or omit to state a materialfact necessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the periodcovered by this quarterly report;

 

3. Based on my knowledge, the financial statements,and other financial information included in this quarterly 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 thisquarterly report;

 

4. The registrant’s other certifying officer and I areresponsible for establishing and maintaining disclosure controls and procedures(as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrantand we have:

 

a) designed such disclosure controls and procedures,or caused such disclosure controls and procedures to be designed under oursupervision, to ensure that material information relating to the registrant,including its consolidated subsidiaries, is made known to us by others withinthose entities, particularly during the period in which this quarterly reportis being prepared;

 

b) evaluated the effectiveness of the registrant’sdisclosure controls and procedures and presented in this quarterly report ourconclusions about the effectiveness of the disclosure controls and procedures,as of the end of the period covered by this quarterly report based on suchevaluation; and

 

c) disclosed in this quarterly report any change inthe registrant’s internal control over financial reporting that occurred duringthe registrant’s most recent fiscal quarter that has materially affected, or isreasonably likely to materially affect, the registrant’s internal control overfinancial reporting; and

 

5. The registrant’s other certifying officer and Ihave disclosed, based on our most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the audit committee ofregistrant’s board of directors (or persons performing equivalent 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, that involvesmanagement or other employees who have a significant role in the registrant’sinternal control over financial reporting.

 

 
|   | Date:   August 26, 2004           |
|--------|---------------------------------------------|
|   |                                        |
|   |                                        |
|   | /s/ John B. Simmons                         |   |
|   | John B. Simmons                             |
|   | Vice President and Chief  Financial Officer |
|   | (Principal Financial  Officer)              |

 

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