The exteriors of the beautiful house of Sidney (Sir Michael Caine) and Myra Bruhl (Dyan Cannon) in this movie were portrayed by a home on Long Island, complete with its own windmill. It has since been bought by Robert Downey Jr.. Interiors of the house were filmed at the "Pathé" Studios in New York City's East Harlem. The stage scenes that bookend this movie were filmed at Music Box Theatre on 239 West 45th Street, New York City, where the original "Deathtrap" stage play the movie was based upon was still running. The play's set was used for the two theatrical stage sequences in this movie.
When this movie was made and released, Christopher Reeve was at the peak of his fame as a result of playing the title character in "Superman (1978)" and "Superman II (1980)," and was about to appear in "Superman III (1983)." Reeve accepted the role of Clifford Anderson because it had nothing to do with either Clark Kent or Superman, and he wished to avoid being typecast by his superhero persona. During the making of this movie, he said, "I've had a lot of training as an actor, and I want to use it."
Director Sidney Lumet once commented on the real stage-play scenes seen in this movie: "We used the original set of 'Deathtrap' as our set for Sidney Bruhl's flop play. The Music Box (Theatre) is dark on Mondays, so we shot there on a Monday, along with six hundred dress extras as first-nighters. Thus, the opening scene is a movie of a play-within-a-play which takes place within the play on which the movie is based. If that's not completely clear, it's at least a 'first'!"
Sir Michael Caine once described his character of Sidney Bruhl in this movie: "He's a very successful mystery writer, with expensive tastes and a sick wife, whose macabre muse has deserted him. He has always assumed that committing crime on paper siphons one's hostilities. But now, after a lifetime of vicarious murder, Bruhl finds himself fantasizing the real thing. Even so, I kept asking myself - how do you explain his strange behavior? Childhood trauma? A deep-rooted compulsion? The stigma of a name like Sidney? No, that's all too simple. The answer is that he's mad - stark raving mad! It's a lovely role."
Sir Michael Caine once said of this movie: "We all swore an oath in blood, well, perhaps it was chablis, not to spoil the fun by running off at the mouth. This thing has more twists than the Grande Corniche. And there is nothing worse than seeing a mystery after some twit has told you the butler did it. That's hypothetical, of course. There's no butler in 'Deathtrap.' We're very democratic that way."