Exhibit 4.1

EXECUTION VERSION

FIRST AMENDMENT TO RIGHTS AGREEMENT

     This First Amendment to Rights Agreement, dated as of March 6, 2008 (this “Amendment”), is between TESORO CORPORATION, a Delaware corporation (the “Company”), and AMERICAN STOCK TRANSFER & TRUST COMPANY, a New York corporation (the “Rights Agent”).

W I T N E S S E T H:

     WHEREAS, the Rights Agent and the Company are parties to that certain Rights Agreement, dated as of November 20, 2007 (the “Rights Agreement”);

     WHEREAS, pursuant to Section 27 of the Rights Agreement, the Company may, and the Rights Agent shall if the Company so directs, supplement or amend any provision of the Rights Agreement in any respect, without the approval of any holders of Rights, during such time as the Rights are redeemable;

     WHEREAS, the Rights are currently redeemable;

     WHEREAS, the Board of Directors of the Company has determined to amend the Rights Agreement in certain respects; and

     WHEREAS, the Company has delivered to the Rights Agent a certificate stating that this Amendment complies with Section 27 of the Rights Agreement and has directed the Rights Agent to amend the Rights Agreement as set forth herein.

     NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the Company and the Rights Agent hereby agree as follows:

     Section 1. Certain Definitions. Capitalized terms used in this Amendment but not otherwise defined shall have the meanings given to such terms in the Rights Agreement.

     Section 2. Amendments. Section 7(a) of the Rights Agreement is hereby deleted and replaced in its entirety with the following paragraph:

     Section 7. Exercise of Rights: Purchase Price; Final Expiration Date of Rights.

     (a) The registered holder of any Right Certificate may exercise the Rights evidenced thereby (except as otherwise provided herein) in whole or in part at any time after the Distribution Date upon surrender of the Right Certificate, with the form of election to purchase on the reverse side thereof duly executed, to the Rights Agent at the office of the Rights Agent designated for such purposes together with payment of the Purchase Price for each one one-thousandth of one share of the Preferred Stock as to which the Rights are exercised, at or prior to the earliest of (i) the close of business on March 6, 2008 (the “Final Expiration Date”), or (ii) the time at which the Rights are redeemed as provided in Section 23 (“Redemption Date”), or (iii) the time at which such Rights are exchanged as provided for in Section 24.

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     Section 3. Remaining Terms. All other provisions of the Rights Agreement that are not expressly amended hereby shall continue in full force and effect. Notwithstanding the foregoing, the Rights Agent and the Company acknowledge and agree that upon the Final Expiration Date (as amended hereby), the Rights Agreement shall terminate and be of no further force and effect.

     Section 4. Severability. If any term, provision, covenant or restriction of this Amendment is held by a court of competent jurisdiction or other authority to be invalid, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions of this Amendment shall remain in full force and effect and shall in no way be affected, impaired or invalidated.

     Section 5. Governing Law. This Amendment shall be deemed to be a contract made under the laws of the State of Delaware and for all purposes shall be governed by and construed in accordance with the laws of such state applicable to contracts to be made and performed entirely within such state.

     Section 6. Descriptive Headings; References. Descriptive headings of the several sections of this Amendment are inserted for convenience only and shall not control or affect the meaning or construction of any of the provisions hereof.

     Section 7. Counterparts. This Amendment may be executed in any number of counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument.

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     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be duly executed and their respective seals to be hereunto affixed and attested, all as of the day and year first above written.

Attest:			TESORO CORPORATION
By	/s/ Otto C. Schwethelm		By	/s/ Charles S. Parrish
	Name:	Otto C. Schwethelm		Name:	Charles S. Parrish
	Title:	Vice President, Chief Financial Officer		Title:	Senior Vice President, General Counsel and Secretary
			AMERICAN STOCK TRANSFER & TRUST COMPANY
			By:	/s/ Herb Lemmer
				Name:	Herb Lemmer
				Title:	Vice President

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