EIGHTH AMENDMENT TO
                                CREDIT AGREEMENT


     This EIGHTH  AMENDMENT TO CREDIT  AGREEMENT  (this  "Amendment") is entered
into  as of  March  14,  2001,  by  and  between  Smithway  Motor  Xpress,  Inc.
("Borrower"),  Smithway  Motor Xpress Corp. as Guarantor (the  "Guarantor")  and
LaSalle Bank National  Association,  formerly known as LaSalle National Bank, as
Lender (the "Lender").

                              W I T N E S S E T H:

     WHEREAS,  the Borrower and the  Guarantor  entered into a Credit  Agreement
dated as of September 3, 1997, a First Amendment to Credit Agreement dated as of
March 1, 1998,  a Second  Amendment  to Credit  Agreement  dated as of March 15,
1998,  a Third  Amendment  to Credit  Agreement  dated as of October 30, 1998, a
Fourth  Amendment  to Credit  Agreement  dated as of August  20,  1999,  a Fifth
Amendment to Credit  Agreement  dated as of December 17, 1999, a Sixth Amendment
to Credit  Agreement dated as of July 1, 2000 and a Seventh  Amendment to Credit
Agreement  dated  as of  August  25,  2000  (collectively  referred  to  as  the
"Agreement"); and

     WHEREAS, the Borrower has requested certain  modifications to the Agreement
and the Lender is willing to do so on the following terms and conditions; and

     NOW, THEREFORE,  in consideration of the mutual agreements,  provisions and
covenants contained herein, the parties agree as follows:

     1. Unless otherwise stated herein,  all of the capitalized  terms contained
in this document shall have the same meanings as contained in the Agreement.

     2. Section  1.1(a) of the  Agreement  is  deleted in its  entirety  and is
replaced with the following:

               (a) The Revolving  Credit.  The Lender  agrees,  on the terms and
          conditions  hereinafter set forth, to make Loans to the Borrower (each
          such Loan, a  "Revolving  Loan") from time to time on any Business Day
          during the period from the Closing Date to the  Revolving  Termination
          Date, in an aggregate amount not to exceed at any time outstanding the
          amount of  $32,500,000  (Thirty  Two  Million  Five  Hundred  Thousand
          Dollars) (the "Revolving Commitment");  provided, however, that, after
          giving  effect to any  Borrowing of  Revolving  Loans,  the  aggregate
          principal  amount of all outstanding  Revolving Loans shall not exceed
          the Maximum Revolving Loan Balance.  Within the limits of the Lender's
          Revolving  Commitment,  and subject to the other terms and  conditions
          hereof, the Borrower may borrow under this subsection  1.1(a),  prepay
          and  reborrow  pursuant  to  this  subsection   1.1(a).  The  "Maximum
          Revolving Loan Balance" will be the lesser of the sum of the Borrowing
          Base in effect  from time to time plus the face  amount of all Letters
          of Credit  outstanding from time to time, or the Revolving  Commitment
          then in effect. If at



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          any time  the  Revolving  Loans  exceed  the  Maximum  Revolving  Loan
          Balance,  Revolving  Loans  must be  repaid  immediately  in an amount
          sufficient to eliminate any excess.

               The Borrower shall be irrevocably and unconditionally  obligated,
          forthwith without presentment, demand, protest or other formalities of
          any kind,  to reimburse  the Lender for any amounts paid by the Lender
          under any Letter of Credit. The Borrower hereby authorizes and directs
          the Lender,  at the Lender's  option,  to make a Revolving Loan in the
          amount of any payment made by the Lender with respect to any Letter of
          Credit.  All amounts  paid by the Lender with respect to any Letter of
          Credit  that  are not  immediately  repaid  by the  Borrower  with the
          proceeds of a Revolving  Loan or otherwise  shall bear interest at the
          interest rate then applicable to Revolving Loans, calculated using the
          Prime Rate and the Applicable Margin in effect.

     3. Section 1.2 of the  Agreement is deleted in its entirety and is replaced
with the following:

          Note.  The Revolving  Loans made by the Lender shall be evidenced by a
          single  Revolving Note payable to the order of the Lender in an amount
          equal to $32,500,000.00 executed by the Borrower, in substantially the
          form of Exhibit A hereto.

     4. Section 6.9 of the  Agreement is deleted in its entirety and is replaced
with the following:

          Total  Indebtedness.  The total consolidated  Indebtedness  (excluding
          indebtedness  between  Guarantor's  consolidated  group  of  companies
          outstanding  pursuant to the SMSD  Transactions)  of Guarantor and its
          Subsidiaries   (including  Borrower)  shall  not  exceed  $65,000,000.
          Neither SMSD nor Guarantor will incur any unconsolidated  Indebtedness
          other than  Indebtedness  to Lender.  The  indebtedness of Borrower to
          SMSD  arising   pursuant  to  SMSD   Transactions   shall  not  exceed
          $35,000,000  prior to  September  30,  2001,  $37,500,000  on or after
          September 30, 2001, but prior to September 30, 2002. $40,300,000 on or
          after  September  30,  2002,  but prior to  September  30,  2003,  and
          $43,400,000 at anytime thereafter."

     5. The  requirement  to comply  with  Section  6.17 for the  period  ending
December 31, 2000 is hereby waived.

     6. The  following  definition  contained in Section 9.1 of the Agreement is
deleted in its entirety and is replaced with the following:

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          "Borrowing Base" means an amount as of any time of determination equal
          to the sum of: (a) eighty five percent (85%) of the  aggregate  amount
          of the  Borrower's  and East West's then existing  Eligible  Accounts,
          provided,  however,  that  the  percentage  advance  against  Eligible
          Accounts  may be  reduced  to  80% in  Lender's  sole  and  absolution
          discretion upon not less than 60 days prior written notice to Borrower
          after review of the results of a field audit examination  conducted by
          Lender,  plus (i) fifty five percent  (55%) of the  aggregate net book
          value of the  Borrower's  and East West's trucks and trailers on which
          Bank has a  perfected  first  security  interest.  Net  book  value is
          defined as the  depreciated  book value of all of Borrower's  and East
          West's  trucks and  trailers  pledged to Lender.  In the event (i) the
          ratio of (x) Borrower's  Consolidated  Net Income before deduction for
          interest and taxes to (y) actual interest  expense,  calculated at the
          end of each fiscal  quarter  hereafter for the  immediate  three month
          period then ending,  is greater than 2.00 to 1.00,  and (ii)  Borrower
          has a net profit of at least $1.00 for the same fiscal  period,  then,
          effective  upon the date of delivery of a  compliance  certificate  by
          Borrower showing such calculations, the borrowing base with respect to
          trucks and trailers  shall be increased  from fifty five percent (55%)
          to sixty percent (60%) until such time as such ratio is less than 2.00
          to 1.00, in which event the borrowing base on truck and trailers shall
          again be reduced to fifty five percent (55%).

     7. Lender, or any persons designated by it, shall have the right to call at
Borrower's places of business at any reasonable times, and, without hindrance or
delay, to inspect the Collateral and to inspect,  audit, check and make extracts
from   Borrower's   books,   records,   journals,   orders,   receipts  and  any
correspondence and other data relating to Borrower's business, the Collateral or
any  transactions  between the parties hereto,  and shall have the right to make
such  verification   concerning  Borrower's  business  as  Lender  may  consider
reasonable under the  circumstances.  Borrower  authorizes Lender to discuss the
affairs,  finances  and  business of Borrower  with any  officers,  employees or
directors of Borrower,  and to discuss the financial  condition of Borrower with
Borrower's independent public accountants. Any such discussions shall be without
liability to Lender or to Borrower's  independent public  accountants.  Borrower
shall  pay to  Lender  all  out-of-pocket  expenses  incurred  by  Lender in the
exercise of its rights  hereunder,  and all of such  expenses  shall  constitute
Liabilities hereunder, shall be payable on demand.

     8. This Amendment will become effective upon:

               (a) the  execution  and  delivery  of this  Amendment  by each of
          Borrower, Guarantor, East West and SMSD; and

               (b) the payment of an amendment fee of $35,000.00.

     After the  required  deliveries  and  payments  are made to the Bank,  this
Amendment will be deemed effective as of March 1, 2001,  provided that Section 5
hereof will be deemed effective as of December 29, 2000.


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     9. Borrower shall pay 50% of the legal fees incurred in connection with the
preparation  of this  Amendment and the documents  and  instruments  referred to
herein,  and shall pay 100% of all out of pocket costs incurred by the Lender or
its attorneys.

     10.  Borrower  expressly  acknowledges  and  agrees  that  all  collateral,
security  interests,  liens,  pledges,  and  mortgages  heretofore,  under  this
Amendment, or hereafter granted to Lender, including,  without limitation,  such
collateral,  security interests,  liens, pledges and mortgages granted under the
Agreement,  and all other supplements to the Agreement,  extend to and cover all
of the  obligations  of Borrower to Lender,  now existing or  hereafter  arising
including,  without limitation,  those arising in connection with the Agreement,
as amended by this Amendment,  upon the terms set forth in such agreements,  all
of which security interests,  liens, pledges, and mortgages are hereby ratified,
reaffirmed, confirmed and approved.

     11.  Borrower  represents  and  warrants  to  Lender  that  (i) it has  all
necessary  power and authority to execute and deliver this Amendment and perform
its  obligations  hereunder,  (ii) this Amendment and the Agreement,  as amended
hereby,  constitute the legal, valid and binding obligations of Borrower and are
enforceable   against  Borrower  in  accordance  with  their  terms,  (iii)  all
representations  and  warranties  of Borrower  contained  in the  Agreement,  as
amended,  and all other  agreements,  instruments  and other  writings  relating
thereto, are true, correct and complete as of the date hereof, and (iv) no Event
of Default, except as waived by this Amendment, exists under the Agreement.

     12. The parties hereto  acknowledge and agree that the terms and provisions
of this Amendment amend,  add to and constitute a part of the Agreement.  Except
as  expressly  modified and amended by the terms of this  Amendment,  all of the
other terms and  conditions  of the  Agreement,  as amended,  and all  documents
executed in connection  therewith or referred to or incorporated  therein remain
in full  force and effect and are hereby  ratified,  reaffirmed,  confirmed  and
approved.

     13. If there is an express conflict between the terms of this Amendment and
the terms of the Agreement, or any of the other agreements or documents executed
in connection  therewith or referred to or  incorporated  therein,  the terms of
this Amendment shall govern and control.

     14. This  Amendment  may be executed in one or more  counterparts,  each of
which shall be deemed to be an original.

     15. This  Amendment  was  executed and  delivered in Chicago,  Illinois and
shall be governed by and  construed in  accordance  with the  internal  laws (as
opposed to conflicts of law provisions) of the State of Illinois.

     IN WITNESS WHEREOF,  this Eighth Amendment has been duly executed as of the
day and year specified at the beginning hereof.


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                                        SMITHWAY MOTOR XPRESS, INC., as Borrower

                                        By:  /s/ G. Larry Owens
                                        Title:  Exec. V.P.

                                        Address  Notice:
                                        P.O.  Box 404
                                        Fort  Dodge,  Iowa 50501
                                        Attn:  G. Larry  Owens
                                        Facsimile: (515) 576-3304
                                        Tel: (515) 576-7418


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                                        SMITHWAY MOTOR XPRESS CORP., as
                                        Guarantor

                                        By:  /s/ G. Larry Owens
                                        Title:    Exec. V.P.

                                        Address Notice:
                                        P.O. Box 404
                                        Fort Dodge, Iowa 50501
                                        Attn: G. Larry Owens
                                        Facsimile: (515) 576-3304
                                        Tel: (515) 576-7418

                                        LASALLE BANK NATIONAL ASSOCIATION,
                                        as Lender

                                        By:  David A. Chaika
                                        Title:  AVP

                                        Address notices and Lending Office:
                                        135 South LaSalle Street
                                        Chicago, Illinois 60603
                                        Attn: Mr. David A. Chaika
                                        Facsimile: (312) 904-6150

                            CONSENT AND RATIFICATION

     The undersigned, pursuant to that certain Guaranty dated as of September 3,
1997,  is a guarantor  of all of the  obligations  of the Borrower to the Lender
under the terms of the Agreement and hereby consents to the Eighth  Amendment to
the Agreement.  Guarantor  hereby  reaffirms and ratifies his guaranty as if the
same were fully set forth herein.

                                     SMITHWAY MOTOR XPRESS CORP., as Guarantor

                                     By:  /s/ G. Larry Owens
                                     Title:    Exec. V.P.


     The  undersigned,  pursuant to that certain  Guaranty dated as of March 15,
1998,  is a guarantor  of all of the  obligations  of the Borrower to the Lender
under the terms of the Agreement

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and hereby consents to the Eighth  Amendment to the Agreement.  Guarantor hereby
reaffirms and ratifies his guaranty as if the same were fully set forth herein.

                                     EAST WEST MOTOR EXPRESS, INC., as Guarantor


                                     By:  /s/ G. Larry Owens
                                     Title:    Exec. V.P.

     The undersigned, pursuant to that certain Guaranty dated as of December 17,
1999,  is a guarantor  of all of the  obligations  of the Borrower to the Lender
under the terms of the Agreement and hereby consents to the Eighth  Amendment to
the Agreement.  Guarantor  hereby  reaffirms and ratifies his guaranty as if the
same were fully set forth herein.

                                     SMSD ACQUISITION CORP., a South Dakota
                                     corporation, as Guarantor


                                     By:  /s/ G. Larry Owens
                                     Title:    Exec. V.P.





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                                    EXHIBIT A

                            AMENDED AND RESTATED NOTE


$32,500,000                                                 As of March 14, 2001


     Smithway Motor Xpress, Inc. an Iowa corporation (the "Borrower"),  promises
to pay to the order of LaSalle Bank  National  Association  (the  "Lender")  the
lesser of the principal sum of Thirty Two Million Five Hundred  Thousand Dollars
($32,500,000)  or the aggregate unpaid principal amount of all Loans made by the
Lender to the Borrower  pursuant to Article II of the Credit  Agreement  (as the
same may be amended or modified,  the "Agreement")  hereinafter  referred to, in
immediately  available  funds  at the  main  office  of  LaSalle  Bank  National
Association in Chicago, Illinois, together with interest on the unpaid principal
amount  hereof at the rates  and on the  dates set forth in the  Agreement.  The
Borrower shall pay the principal of and accrued and unpaid interest on the Loans
in full on the Revolving Termination Date.

     The Lender shall record in accordance  with its usual  practice,  the date,
amount and interest rate of each Loan and the date and amount of each  principal
and interest payment hereunder.

     This Note is issued  pursuant  to, and is entitled to the  benefits of, the
Credit Agreement, dated as of September 3, 1997 between the Borrower and Lender,
to which Agreement,  as it may be amended from time to time, reference is hereby
made for a statement of the terms and conditions  governing this Note, including
the terms and  conditions  under which this Note may be prepaid or its  maturity
date accelerated. Capitalized terms used herein and not otherwise defined herein
are used with the meanings attributed to them in the Agreement.


                                         SMITHWAY MOTOR XPRESS, INC.


                                         By: /s/ G. Larry Owens
                                         Print Name: G. Larry Owens
                                         Title:    Exec. V.P.

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