 | George Nader als Glenn Martin |
 | Barbara Nichols als Gale Wilson |
 | George Macready als Prof. Vaughn Dornheimer |
 | Dolores Faith als Lisa Dornheimer |
 | Hugh Beaumont als Austin Welles |
 | Richard Arlen als National Intelligence |
 | Richard Kiel als Dr. Kolos |
 | John Indrisano als Thor, the Butler |
| Ted Durant als The Galaxy Being |
| Tommy Leonetti als Reporter (uncredited) |
| Walter Maslow |
| Larry Barton |
| Lori Lyons |
| Benito Prezia |
| Margaret Teele als Blonde Lab Assistant |
 | Alean 'Bambi' Hamilton als Brunette Lab Assistant |
 | Walter Abel als Dr. Munson |
 | Lon Satton |
| Mel Ruick als Dr. Munson (as Melville Ruick) |
| Kim Satana als Dr. Lin Yung |
| John Dasten als (as John Daston) |
| Richard Schuyler |
| William White als (as Bill Hampton) |
| Lon Satton als Reporter (uncredited) |
| Andrew Johnson als (Uncredited) |
| Hugo Grimaldi | Director |
| Monroe P. Askins | Director of Photography |
| Hugo Grimaldi | Producer |
| Donald Wolfe | Editor |
| Arthur C. Pierce | Writer |
| Arthur C. Pierce | Producer |
| Lawrence Woolner | Executive Producer |
| Paul Sylos | Art Direction |
| John Livesley | Key Grip |
| Kay Shea | Hairstylist |
| John Chambers | Special Effects Makeup Artist |
| Raymond Boltz Jr. | Set Decoration |
| Mickey Meyers | Costume Design |
| Bob Mark | Makeup Artist |
| Jesse Corallo | Production Manager |
| Jesse Corallo | Assistant Director |
| Clancy Herne | Second Assistant Director |
| Ross C. Burke | Property Master |
| Robert Reeve | Sound Effects Editor |
| Jean G. Valentino | Sound Mixer |
| Robert Glenn | Sound Editor |
| Frank Dugas | Camera Operator |
| George Marquenie | Gaffer |
| Marvin Paige | Casting Consultant |
| Roger George | Special Effects |
