1 Exhibit 23(a) INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in this Registration Statement of Tesoro Petroleum Corporation on Form S-4 our report dated February 1, 1995, appearing in the Annual Report on Form 10-K of Tesoro Petroleum Corporation for the year ended December 31, 1994 and to the reference to us under the heading "Experts" in the Prospectus, which is part of this Registration Statement. /s/ DELOITTE & TOUCHE LLP - ---------------------------- Deloitte & Touche LLP San Antonio, Texas January 16, 1996