Anton Diffring as Dr. Schuler

Erika Remberg as Elissa Caro

Yvonne Monlaur as Nicole Vanet

Donald Pleasence as Vanet

Jane Hylton as Angela

Kenneth Griffith as Martin

Conrad Phillips as Inspector Arthur Ames

Jack Gwillim as Supt. Andrews

Vanda Hudson as Magda von Meck

Yvonne Romain as Melina

Colette Wilde as Evelyn Morley

William Mervyn as Dr. Morley

Peter Swanwick as Inspector Knopf

Carla Challoner as Nicole (as a Child)

Kenny Baker as Dwarf

Walter Gotell as Baron Von Gruber

Kenneth J. Warren as First Roustabout

Jack Carson as Chief Eagle Eye

Glyn Houston as Carnival Barker (uncredited)

Reg Thomason as Roustabout (uncredited)

Arthur Dibbs as Circus Audience Member (uncredited)