Oliver Reed as Dr. Hal Raglan

Samantha Eggar as Nola Carveth

Art Hindle as Frank Carveth

Henry Beckman as Barton Kelly

Nuala Fitzgerald as Juliana Kelly

Cindy Hinds as Candice Carveth

Susan Hogan as Ruth Mayer

Gary McKeehan as Mike Trellan

Michael Magee as Inspector

Robert A. Silverman as Jan Hartog

Joseph Shaw as Coroner

Larry Solway as Lawyer

Reiner Schwarz as Dr. Birkin

Felix Silla as Creature

John Ferguson as Creature

Nicholas Campbell as Chris

Mary Swinton as Wendy

Jerry Kostur as Construction Worker

Chris Britton as Man in Auditorium

Elijah Siegler as Samson (uncredited)