EXHIBIT 23 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in the Registration Statements on Form S-3 (Nos. 33-63719 and 333-58415-01) of Unocal Corporation of our report dated February 14, 2002, relating to the consolidated financial statements and financial statement schedule, which appears in this Annual Report on Form 10-K/A (Amendment No. 2) for the year ended December 31, 2001. /s/PricewaterhouseCoopers LLP - ------------------------------ PricewaterhouseCoopers LLP Los Angeles, California September 23, 2002