William Holden as Richard Thorn

Lee Grant as Ann Thorn

Jonathan Scott-Taylor as Damien Thorn

Robert Foxworth as Paul Buher

Nicholas Pryor as Charles Warren

Lew Ayres as Bill Atherton

Sylvia Sidney as Aunt Marion

Lance Henriksen as Sergeant Neff

Lucas Donat as Mark Thorn

Elizabeth Shepherd as Joan Hart

Ian Hendry as Michael Morgan (uncredited)

Leo McKern as Carl Bugenhagen (uncredited)

Allan Arbus as Pasarian

Fritz Ford as Murray

Meshach Taylor as Dr Kane

John J. Newcombe as Teddy

John Charles Burns as Butler

Paul Cook as Colonel

Diane Daniels as Jane

Robert E. Ingham as Teacher

William B. Fosser as Minister

Corney Morgan as Greenhouse Technician

Russell P. Delia as Truck Driver

Judith Dowd as Maid

Thomas O. Erhart Jr. as Sergeant #1

Sorin Serene Pricopie as Pasarian's Assistant

Robert J. Jones Jr. as Tour Guide

Rusdi Lane as Jim Gardner

Charles Mountain as Burial Priest

Cornelia Sanders as Young Girl

Felix Shuman as Dr. Fiedler

James Spinks as Technician #1

Owen Sullivan as Byron

William J. Whelehan as Security Guard