Convicted killer John Winfield was executed by lethal injection just after midnight for the death of two St. Louis women.
The crime happened in 1996 when Winfield shot former girlfriend Carmelita Donald along with her friends Arthea Sanders and Shawnee Murphy in a jealous rage.
All three victims were shot in the head by Winfield, killing both Sanders and Murphy while leaving Donald blinded.
Requests to halt the execution over the secretive process Missouri uses to obtain its lethal injection drug pentobarbital were denied by both the Supreme court and Missouri Governor Jay Nixon.
Nixon said he rejected Winfield's request for clemency because he felt the heinous nature of the crimes he was found guilty of warranted the death penalty.
He was the fifth inmate Missouri has executed this year and the seventh since the state resumed executions using the controversial execution drug pentobarbital this past November.
Winfield's execution came just an hour after convicted killer Marcus Wellons was put to death in Georgia for the 1989 rape and murder of his 15 year old neighbor India Roberts.
Wednesday's executions were the first to take place in the United States since April 29 when a botched execution of convicted Oklahoma killer Clayton Lockett raised new concerns over the lethal injection process.
Neither of Wednesday's executions had any noticeable complications.
The execution of convicted Florida killer John Ruthell Henry is also scheduled to take place Wednesday night.