George C. Scott

Lt. William 'Bill' Kinderman

Ed Flanders

Father Joseph Kevin Dyer

Brad Dourif

James Venamun / The Gemini Killer

Jason Miller

Father Damien Karras / Patient X

Nicol Williamson

Father Morning

Scott Wilson

Dr. Temple

Nancy Fish

Nurse Allerton

George DiCenzo

Stedman

Don Gordon

Ryan

Lee Richardson

University President

Grand L. Bush

Sergeant Atkins

Mary Jackson

Mrs. Clelia

Viveca Lindfors

Nurse X

Ken Lerner

Dr. Freedman

Tracy Thorne

Nurse Keating

Barbara Baxley

Shirley

Zohra Lampert

Mary Kinderman

Harry Carey, Jr.

Father Kanavan

Clifford David

Dr. Bruno

Alex Zuckerman

Korner Boy

Lois Foraker

Nurse Merrin

Tyra Ferrell

Nurse Blaine

Kevin Corrigan

Altar Boy

Walt MacPherson

Police Sergeant

David Dwyer

Second Police Officer

Danny Epper

Police Driver

Samuel L. Jackson

Dream Blind Man

Jodi Long

First Dream Woman (uncredited)

Amelia Campbell

Young Girl in Dream (uncredited)

Larry King

Larry King

Patrick Ewing

Angel of Death

Clinton Brandhagen

Young Boy in Dream (uncredited)

Colleen Dewhurst

Satan (voice) (uncredited)

Fabio

Angel (uncredited)

Jeff Henry

Angel (uncredited)

Patt Noday

Hospital Ward Priest (uncredited) (unconfirmed)

Teresa Wright

Penitent (uncredited)

Charles Edwin Powell

Patient X Possessed