The house used in the film, known in real life as the historic 'Dunsmuir House', is located in Oakland, California. It is also featured in: Little Girls Blue (1978), Phantasm (1979), Dangereusement vôtre (1985), The Vineyard (1989), Quand Harriet découpe Charlie (1993), and Jugé coupable (1999).
Bette Davis reportedly had conflicts with Karen Black, feeling Black did not extend her an appropriate degree of respect, and that her behavior on the film set was unprofessional.
Bette Davis detested Oliver Reed, refering to him as "that man" and only speaking to him when they shared onscreen dialogue. After filming, she described him as "possibly one of the most loathesome human beings I have ever had the misfortune of meeting".
According to director, Dan Curtis, there were no sets built for the film. It was filmed entirely on location.
The haunting flashbacks that Ben Rolf has about the creepy chauffeur are not based on anything in the original Marasco novel, but were based on an actual childhood experience of Dan Curtis. Curtis recalled as a young child being at his mother's funeral and seeing a chauffeur laughing outside of the funeral parlor which disturbed him deeply. He wrote the memory into the film, and the chauffeur became a most eerie character.