Michael Sarrazin (Peter Proud)
Jennifer O'Neill (Ann Curtis)
Margot Kidder (Marcia Curtis)
Cornelia Sharpe (Nora Hayes)
Paul Hecht (Dr. Samuel Goodman)
Terry Green (College Student)
Fred Stuthman (Pop Johnson)
Mary Margaret Amato (Nurse)
Addison Powell (Reeves)
Sam Laws (Satan's Disciple)
Albert Henderson (Police Sergeant)
Steve Franken (Dr. Charles Crennis)
Lester Fletcher (Car Salesman)
Phillip Clark (Number Five)
Tony Stephano (Jeff Curtis)
Norman Burton (Dr. Frederick Spear)
Anne Ives (Ellen Curtis)
Debra Scott (Suzy)