Sam Peckinpah wrote the original script and was set to direct, but Yul Brynner didn't like the script because it made Pancho Villa - a man who had given standing orders to shoot all prisoners - "look like a bad guy". Peckinpah was fired and his script was rewritten by Robert Towne to conform to Brynner's idea of what Villa was like.
One of the extras in the film, playing a Mexican guerrilla girl, is Turkish singer Seyyal Taner. She would later receive notoriety for scoring no points in the 1987 Eurovision song contest.
This is the first movie where Charles Bronson appears with his trademark mustache.