 | Richard Derr als David Randall |
 | Barbara Rush als Joyce Hendron |
 | Peter Hansen als Dr. Tony Drake |
 | John Hoyt als Sydney Stanton |
 | Larry Keating als Dr. Cole Hendron |
 | Rachel Ames als Julie Cummings |
 | Stephen Chase als Dr. George Frye |
 | Frank Cady als Harold Ferris |
 | Hayden Rorke als Dr. Emery Bronson |
 | Sandro Giglio als Dr. Ottinger |
 | Kirk Alyn als Rioter Bringing Guns (uncredited) |
 | James Congdon als Eddie Garson (uncredited) |
 | Gertrude Astor als Traveler (uncredited) |
 | Robert Chapman als Student (uncredited) |
| Gene Collins als Newsdealer (uncredited) |
| Marcel De La Brosse als Headwaiter (uncredited) |
 | Estelle Etterre als Traveler (uncredited) |
 | Paul Frees als Narrator/U.S. President (voice) |
| Gay Nelson als Leda (uncredited) |
| Edna Smith |
 | Mary Murphy als Student |
| Arthur P. Schmidt | Editor |
| Sydney Boehm | Screenplay |
| Albert Nozaki | Art Department Assistant |
| Leith Stevens | Original Music Composer |
| Rudolph Maté | Director |
| John F. Seitz | Director of Photography |
| George Pal | Producer |
| W. Howard Greene | Director of Photography |
| Hal Pereira | Art Department Manager |
| Wally Westmore | Makeup Artist |
| Edith Head | Costume Design |
| Ross Dowd | Set Decoration |
| Philip Wylie | Novel |
| Sam Comer | Set Decoration |
| Edwin Balmer | Novel |
| Walter Oberst | Sound Recordist |
| Gene Merritt | Sound Recordist |
| Michael D. Moore | Assistant Director |
