Brown was given a Sunday noon deadline to choose between a one-drug lethal injection or execution by a three-drug cocktail, but he declined to choose.
Brown's refusal to choose his execution method means that the three-drug cocktail will be used if his execution is not blocked. His execution will be California's first one in nearly five years.
He was sentenced to death for the 1980 rape and murder of 15-year-old Susan Jordan in Riverside. He had been paroled four months earlier from a prison term imposed for the 1977 rape of a 14-year-old girl.
Brown also plans Monday to ask a Marin County Superior Court judge to block his execution while a recently filed lawsuit challenging the state's lethal injection regulations is pending.
The Associated Press contributed to this report.