EXHIBIT 23 CONSENT OF INDEPENDENT ACCOUNTANTS We consent to the incorporation by reference in the Registration Statement of Unocal Corporation on Form S-8 (No. 33-65461) of our report, dated June 18, 1999, on our audits of the financial statements and supplemental schedules of the Molycorp, Inc. 401(k) Retirement Savings Plan as of December 31, 1998 and 1997 and for the years then ended which report is included in this annual report on Form 11-K. PricewaterhouseCoopers LLP Los Angeles, California June 29, 1999