Paul Hubschmid

John McLaren

Fiorella Mari

Mary McLaren

Madeleine Fischer

Katy Dandridge

Ivo Garrani

Professor Herbert Weisse

Dario Michaelis

Peter Leduq

Jean-Jacques Delbo

Sergei Boetnikov

Peter Meersman

General van Dorff (uncredited)

Massimo Zeppieri

Dennis McLaren (uncredited)

Sam Galter

Randowsky

Annie Bernal

Lab Assistant (uncredited)

Giacomo Rossi Stuart

Stuart (uncredited)

Gérard Landry

Landowsky (uncredited)

Shane Rimmer

John McLaren (uncredited) (voice)