**EXHIBIT 31.2**

 

**CHIEF FINANCIAL OFFICER CERTIFICATION**

 

I, John B. Simmons, VicePresident and Chief Financial Officer, certify that:

 

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

 

2. Based on my knowledge,this report does not contain any untrue statement of a material fact or omit tostate a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this report;

 

3. Based on my knowledge,the financial statements, and other financial information included in thisreport, fairly present in all material respects the financial condition,results of operations and cash flows of the registrant as of, and for, theperiods presented in this 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)), and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and 15d-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 thisreport is being prepared;

 

b) Designed such internalcontrol over financial reporting, or caused such internal control overfinancial reporting to be designed under our supervision, to provide reasonableassurance regarding the reliability of financial reporting and the preparationof financial statements for external purposes in accordance with generallyaccepted accounting principles;

 

c) 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

 

d) Disclosed in this reportany change in the registrant’s internal control over financial reporting thatoccurred during the registrant’s most recent fiscal quarter that has materiallyaffected, or is reasonably likely to materially affect, the registrant’sinternal 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 the 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 or notmaterial, that involves management or other employees who have a significantrole in the registrant’s internal control over financial reporting.

 
|   |                                              | Date:  August  25, 2005 |
|--------|---------------------------------------------------|-----------------------------------|
|   |                                              |
|   |                                              |
|   | /s/ John B. Simmons                               |                              |
|   | John B. Simmons                                   |
|   | Senior Vice President and Chief Financial Officer |
|   | (Principal Financial Officer)                     |

 

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