The movie was a passion project of director William Friedkin who called it "the first film I really wanted to make, understood and felt passionate about". He had first seen the play in San Francisco in 1962, and managed to get the film version funded by Edgar J. Scherick at Palomar Pictures, in part because it could be made relatively cheaply. Pinter wrote the screenplay himself and was heavily involved in casting. "To this day I don't think our cast could have been improved," wrote Friedkin later.
There was a ten-day rehearsal period and the shoot went smoothly. Friedkin says the only tense exchange he had with Pinter in a year of working together came when Joseph Losey saw the movie and requested, via Pinter, that Friedkin cut out a mirror shot as it was too close to Losey's style; Friedkin refused as "I wasn't about to destroy the film's continuity to mollify Losey's ego".
The four male members of the six member cast all died within a 4 year period: Robert Shaw on 28 August 1978, Sydney Tafler on 8 November 1979, Moultrie Kelsall on 12 February 1980, and Patrick Magee on 14 August 1982.
Closing credits: All characters and events in this film are fictitious. Any similarity to actual events or persons living or dead is purely coincidental.