 | Paul Hubschmid als John McLaren |
 | Madeleine Fischer als Katy Dandridge |
 | Fiorella Mari als Mary McLaren |
 | Ivo Garrani als Professor Herbert Weisse |
| Dario Michaelis als Peter Leduq |
| Sam Galter als Randowsky |
 | Jean-Jacques Delbo als Sergei Boetnikov |
| Peter Meersman als General van Dorff (uncredited) |
| Massimo Zeppieri als Dennis McLaren (uncredited) |
| Annie Bernal als Lab Assistant (uncredited) |
 | Giacomo Rossi Stuart als Stuart (uncredited) |
 | Gérard Landry als Landowsky (uncredited) |
 | Shane Rimmer als John McLaren (uncredited) (voice) |
| Paolo Heusch | Director |
| Guido Giambartolomei | Producer |
| Carlo Rustichelli | Original Music Composer |
| Mario Bava | Director of Photography |
| Samuel Z. Arkoff | Executive Producer |
| Otello Colangeli | Editor |
| Ubaldo Terzano | Camera Operator |
| Virgilio Sabel | Story |
| Marcello Coscia | Screenplay |
| Sandro Continenza | Screenplay |
| Beni Montresor | Production Design |
| Angelo Malantrucco | Makeup Artist |
| Ada Palombi | Hairstylist |
| Armando Morane | Production Manager |
| Mario Bava | Director |
