EXHIBIT 23

            CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Directors of Smithway Motor Xpress Corp.
The Administrator of the Smithway Motor Xpress, Inc. 401(k)
  Retirement Savings and Investment Plan:

We consent to incorporation by reference in the registration statement (Nos.
333-10249, 333-10251, 333-21253, 333-81855, 333-97195, and 333-126026) on Form
S-8 of Smithway Motor Xpress Corp. of our report dated June 29, 2005, relating
to the statements of net assets available for benefits of the Smithway Motor
Xpress, Inc. 401(k) Retirement Savings and Investment Plan as of December 31,
2004 and 2003, the related statements of changes in net assets available for
plan benefits for the years then ended, and the related schedule, which report
appears in the December 31, 2004, Form 11-K of the Smithway Motor Xpress, Inc.
401(k) Retirement Savings and Investment Plan.

/s/ KPMG LLP
Des Moines, Iowa
June 29, 2005