Ed Begley Jr. as Frank

E.J. André as Mr. McCauley

Ann Doran as Mrs. McCauley

Christina Hart as Helen

Orin Cannon as Old Farmer

Jean Le Bouvier as Mrs. Cantrell

Dick McGarvin as Mr. Dorset

Karen Hurley as Mr. Dorset

Patrick Macnee as Dr. Gheria

Anjanette Comer as Alexis

Elisha Cook Jr. as Karel

Horst Buchholz as Michael

Joan Hackett as Mother

Lee Montgomery as Bobby

Michael Talbott as Vinnie McCauley (uncredited)

Gail Bowman as Maria (uncredited)

John Dehner as Narrator (voice) (uncredited)

Joan Lemmo as Eva (uncredited)

Jeff Reese as Young Man (uncredited)

Lars Green as Demonic Bobby (uncredited)