 | Dana Andrews als Dr. Stephen Sorenson |
 | Janette Scott als Dr. Maggie Sorenson |
 | Kieron Moore als Dr. Ted Rampion |
 | Alexander Knox als Sir Charles Eggerston |
 | Peter Damon als John Masefield |
 | Sydna Scott als Angela |
 | Gary Lasdun als Markov |
 | John Karlsen als Dr. Reynolds |
 | Alfred Brown als Dr. Bill Evans |
 | Mike Steen als Steele |
 | Todd Martin als Simpson |
| Jim Gillen als Rand |
| Ben Tatar als Indian Ambassador |
| Emilio Carrere |
| Andrew Marton | Director |
| Bernard Glasser | Producer |
| Lester A. Sansom | Producer |
| Julian Zimet | Screenplay |
| Jon Manchip White | Screenplay |
| Jon Manchip White | Story |
| Eugène Lourié | Art Direction |
| Carmen Martín | Makeup Artist |
| Tíbor Reves | Production Manager |
| Eugène Lourié | Special Effects |
| Josefa Rubio | Hairstylist |
| Derek Parsons | Editor |
| Alex Weldon | Special Effects |
| Manuel Berenguer | Director of Photography |
| Johnny Douglas | Original Music Composer |
| Laure Lourié | Costume Design |
| Philip Yordan | Executive Producer |
| Isabel Ruiz Capillas | Script Supervisor |
| José María Ochoa | Assistant Director |
| Kurt Herrnfeld | Sound Editor |
| David Hildyard | Sound Recordist |
| Maurice Askew | Sound Recordist |
| Johnny Douglas | Conductor |
