Gregory Peck
as Robert Thorn

Lee Remick
as Katherine Thorn

David Warner
as Keith Jennings

Billie Whitelaw
as Mrs. Baylock

Harvey Stephens
as Damien

Patrick Troughton
as Father Brennan

Martin Benson
as Father Spiletto

Robert Rietti
as Monk

Tommy Duggan
as Priest

John Stride
as Psychiatrist

Holly Palance
as Young Nanny

Anthony Nicholls
as Dr. Becker

Roy Boyd
as Reporter

Sheila Raynor
as Mrs. Horton

Robert MacLeod
as Horton

Bruce Boa
as Thorn's Aide

Don Fellows
as Thorn's Second Aide

Patrick McAlinney
as Photographer

Dawn Perllman
as Chambermaid

Nancy Mannigham
as Nurse

Miki Iveria
as First Nun

Betty McDowall
as American Secretary

Nicholas Campbell
as Marine

Burnell Tucker
as Secret Service Man (uncredited)

Ronald Leigh-Hunt
as Gentleman at Rugby Match (uncredited)

Guglielmo Spoletini
as Italian Taxi Driver (uncredited)

Freda Dowie
as Nun (uncredited)

Ya'ackov Banai
as Arab (uncredited)

Harvey Bernhard
as Man walking across street (uncredited)

Michael Byrne
as Monk (uncredited)

Leo McKern
as Carl Bugenhagen (uncredited)

Bill Reimbold
as General (uncredited)

Michael Leader
as Rugby Match Spectator (uncredited)