Exhibit 10.1

EIGHTH AMENDMENT TO CREDIT AGREEMENT

This EIGHTH AMENDMENT TO CREDIT AGREEMENT (this “Amendment”), made and entered into as of June 27, 2003, is by and between Marten Transport, Ltd., a Delaware corporation (the “Borrower”), the banks which are signatories to the Credit Agreement described below (the “Banks”) and U.S. Bank National Association, a national banking association, as agent for the Banks (in such capacity, the “Agent”).

RECITALS

1.                                       The Agent, the Banks and the Borrower entered into a Credit Agreement dated as of October 30, 1998 as amended by a First Amendment dated as of January 3, 2000, a Second Amendment dated as of January 19, 2000, a Third Amendment dated as of April 5, 2000, a Fourth Amendment dated as of May 31, 2000, a Fifth Amendment dated as of December 6, 2000, a Sixth Amendment dated as of January 14, 2002 and a Seventh Amendment dated as of March 29, 2003 (as amended, restated or otherwise modified from time to time, the “Credit Agreement”); and

2.                                       The Borrower desires to amend certain provisions of the Credit Agreement, and the Agent and the Banks have agreed to make such amendments, subject to the terms and conditions set forth in this Amendment.

AGREEMENT

NOW, THEREFORE, for good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto hereby covenant and agree to be bound as follows:

Section 1.                 Capitalized Terms.  Capitalized terms used herein and not otherwise defined herein shall have the meanings assigned to them in the Credit Agreement, unless the context shall otherwise require.

Section 2.                 Amendment.  The definition of “Letter of Credit Sublimit” contained in Section 1.1 of the Credit Agreement is hereby amended in its entirety to read as follows:

“Letter of Credit Sublimit”:  $6,000,000.

Section 3.                 Effectiveness of Amendments.  The amendments contained in this Amendment shall become effective upon delivery by the Borrower of, and compliance by the Borrower with, the following:

3.1                               This Amendment duly executed by the Borrower.

3.2                               Certified copies of all documents evidencing any necessary corporate action, consent or governmental or regulatory approval (if any) with respect to this Amendment.

3.3                               The Borrower shall have satisfied such other conditions as specified by the Agent and the Banks, including payment of all unpaid legal fees and expenses incurred by the Agent through the date of this Amendment in connection with the Credit Agreement and the Amendment Documents.

Section 4.                 Representations, Warranties, Authority, No Adverse Claim.

4.1                               Reassertion of Representations and Warranties, No Default.  The Borrower hereby represents that on and as of the date hereof and after giving effect to this Amendment (a) all of the representations and warranties contained in the Credit Agreement are true, correct and complete in all respects as of the date hereof as though made on and as of such date, except for changes permitted by the terms of the Credit Agreement, and (b) there will exist no Default or Event of Default under the Credit Agreement as amended by this Amendment on such date which has not been waived by the Banks.

4.2                               Authority, No Conflict, No Consent Required. The Borrower represents and warrants that the Borrower has the power and legal right and authority to enter into the Amendment Documents and has duly authorized as appropriate the execution and delivery of the Amendment Documents and other agreements and documents executed and delivered by the Borrower in connection herewith or therewith by proper corporate action, and none of the Amendment Documents nor the agreements contained herein or therein contravenes or constitutes a default under any agreement, instrument or indenture to which the Borrower is a party or a signatory or a provision of the Borrower’s Certificate of Incorporation, Bylaws or any other agreement or requirement of law, or result in the imposition of any Lien on any of its property under any agreement binding on or applicable to the Borrower or any of its property except, if any, in favor of the Agent.  The Borrower represents and warrants that no consent, approval or authorization of or registration or declaration with any Person, including but not limited to any governmental authority, is required in connection with the execution and delivery by the Borrower of the Amendment Documents or other agreements and documents executed and delivered by the Borrower in connection therewith or the performance of obligations of the Borrower therein described, except for those which the Borrower has obtained or provided and as to which the Borrower has delivered certified copies of documents evidencing each such action to the Agent.

4.3                               No Adverse Claim. The Borrower warrants, acknowledges and agrees that no events have been taken place and no circumstances exist at the date hereof which would give the Borrower a basis to assert a defense, offset or counterclaim to any claim of the Agent or the Banks with respect to the Obligations.

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Section 5.                 Affirmation of Credit Agreement, Further References.  The Agent, the Banks and the Borrower each acknowledge and affirm that the Credit Agreement, as hereby amended, is hereby ratified and confirmed in all respects and all terms, conditions and provisions of the Credit Agreement, except as amended by this Amendment, shall remain unmodified and in full force and effect.  All references in any document or instrument to the Credit Agreement are hereby amended and shall refer to the Credit Agreement as amended by this Amendment.   All of the terms, conditions, provisions, agreements, requirements, promises, obligations, duties, covenants and representations of the Borrower under such documents and any and all other documents and agreements entered into with respect to the obligations under the Credit Agreement are incorporated herein by reference and are hereby ratified and affirmed in all respects by the Borrower.

Section 6.                 Merger and Integration, Superseding Effect.  This Amendment, from and after the date hereof, embodies the entire agreement and understanding between the parties hereto and supersedes and has merged into this Amendment all prior oral and written agreements on the same subjects by and between the parties hereto with the effect that this Amendment, shall control with respect to the specific subjects hereof and thereof.

Section 7.                 Severability.  Whenever possible, each provision of this Amendment and the other Amendment Documents and any other statement, instrument or transaction contemplated hereby or thereby or relating hereto or thereto shall be interpreted in such manner as to be effective, valid and enforceable under the applicable law of any jurisdiction, but, if any provision of this Amendment, the other Amendment Documents or any other statement, instrument or transaction contemplated hereby or thereby or relating hereto or thereto shall be held to be prohibited, invalid or unenforceable under the applicable law, such provision shall be ineffective in such jurisdiction only to the extent of such prohibition, invalidity or unenforceability, without invalidating or rendering unenforceable the remainder of such provision or the remaining provisions of this Amendment, the other Amendment Documents or any other statement, instrument or transaction contemplated hereby or thereby or relating hereto or thereto in such jurisdiction, or affecting the effectiveness, validity or enforceability of such provision in any other jurisdiction.

Section 8.                 Successors.  The Amendment Documents shall be binding upon the Borrower, the Agent and the Banks and their respective successors and assigns, and shall inure to the benefit of the Borrower, the Agent and the Banks and the successors and assigns of the Agent and the Banks.

Section 9.                 Legal Expenses.  As provided in Section 9.2 of the Credit Agreement, the Borrower agrees to reimburse the Agent and the Banks, upon execution of this Amendment, for all reasonable out-of-pocket expenses (including attorney’ fees and legal expenses of Dorsey & Whitney LLP, counsel for the Agent) incurred in connection with the Credit Agreement, including in connection with the negotiation, preparation and execution of the Amendment Documents and all other documents negotiated, prepared and executed in connection with the Amendment Documents, and in enforcing the obligations of the Borrower under the Amendment Documents, and to pay and save the Agent and the Banks harmless from

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all liability for, any stamp or other taxes which may be payable with respect to the execution or delivery of the Amendment Documents, which obligations of the Borrower shall survive any termination of the Credit Agreement.

Section 10.          Headings.  The headings of various sections of this Amendment have been inserted for reference only and shall not be deemed to be a part of this Amendment.

Section 11.          Counterparts.  The Amendment Documents may be executed in several counterparts as deemed necessary or convenient, each of which, when so executed, shall be deemed an original, provided that all such counterparts shall be regarded as one and the same document, and either party to the Amendment Documents may execute any such agreement by executing a counterpart of such agreement.

Section 12.          Governing Law.  THE AMENDMENT DOCUMENTS SHALL BE GOVERNED BY THE INTERNAL LAWS OF THE STATE OF MINNESOTA, WITHOUT GIVING EFFECT TO CONFLICT OF LAW PRINCIPLES THEREOF, BUT GIVING EFFECT TO FEDERAL LAWS APPLICABLE TO NATIONAL BANKS, THEIR HOLDING COMPANIES AND THEIR AFFILIATES.

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed as of the date and year first above written.

[Signature Page to Eighth Amendment to Credit Agreement]

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