Ronald Lott, 53, was executed late yesterday and pronounced dead at 0006 GMT today said Jerry Massie, a spokesman for the prison system in the southern US state.
Lott's victims, one of whom was in her 80s and the other in her 90s, were both raped before they were killed in separate attacks in the mid-1980s.
It was the 37th execution this year in the United States and the fifth in Oklahoma, according to the Death Penalty Information Center, which monitors capital punishment cases in the United States.