 | Albert Dekker als Dr. Alexander Thorkel |
 | Thomas Coley als Bill Stockton |
 | Janice Logan als Dr. Mary Robinson |
 | Charles Halton als Dr. Rupert Bulfinch |
 | Victor Kilian als Steve Baker |
 | Frank Yaconelli als Pedro |
 | Paul Fix als Dr. Mendoza |
 | Frank Reicher als Prof. Kendall |
| Jane Webb als Woman |
| Billy Wilkerson als Silent Indian |
| Dale Van Every | Producer |
| Gerard Carbonara | Original Music Composer |
| A. E. Freudeman | Set Designer |
| Ernest B. Schoedsack | Director |
| Tom Kilpatrick | Screenplay |
| Merian C. Cooper | Producer |
| Henry Sharp | Director of Photography |
| Malcolm Stuart Boylan | Screenplay |
| Ellsworth Hoagland | Editor |
| Albert Hay Malotte | Original Music Composer |
| Ernst Toch | Original Music Composer |
| William LeBaron | Executive Producer |
| Hans Dreier | Art Direction |
| A. Earl Hedrick | Art Direction |
| Robert Odell | Art Direction |
| Charles Gemora | Makeup Artist |
| Hollingsworth Morse | Assistant Director |
| Harry Lindgren | Sound Recordist |
| Richard Olson | Sound Recordist |
