Trivia: In the scene where Regan's mother is supernaturally blasted away from the bedside, she is being yanked by the crew by a length of rope. After dozens of takes director William Friedkin was still unhappy with the look of the shot and ordered the crew to haul her more fiercely. The scream in the shot that made the cut was of genuine pain and required no dubbing for effect.
Trivia: Christopher Lee did this movie for free, and considers it one of his best roles ever.
Trivia: Despite repeated citations in print, (as recently as the 2001 edition of 'Film Facts' by Patrick Robertson), both Donald Sutherland and Julie Christie maintain that the sex scene between them was, in fact simulated, and they did not actually have sex, as has been widely reported.
Trivia: One of the movie critics that Edward Lionhart kills in the movie is Miss Chloe Moon, played by Coral Browne. In real life, Vincent Price and Coral Browne fell madly in love while making this movie, and they married shortly afterward, and remained married until her death in 1991.