 | Boris Karloff als Nahum Witley |
 | Nick Adams als Stephen Reinhart |
 | Suzan Farmer als Susan Witley |
 | Freda Jackson als Letitia Witley |
 | Terence de Marney als Merwyn |
 | Patrick Magee als Dr. Henderson |
 | Sheila Raynor als Miss Bailey |
 | Harold Goodwin als Taxi Driver |
 | Paul Farrell als Jason |
 | Sydney Bromley als Pierce |
 | Billy Milton als Henry |
 | Leslie Dwyer als Potter |
| Daniel Haller | Director |
| Alfred Cox | Editor |
| Pat Green | Producer |
| Samuel Z. Arkoff | Executive Producer |
| Colin Southcott | Art Direction |
| James H. Nicholson | Executive Producer |
| Paul Beeson | Director of Photography |
| Don Banks | Original Music Composer |
| Jerry Sohl | Screenplay |
| Ken Rawkins | Sound Recordist |
| Wally Veevers | Special Effects |
| Dennis Hall | Assistant Director |
| Tilly Day | Continuity |
| Bobbie Smith | Hairstylist |
| Ernie Sullivan | Special Effects |
| Cecil Cooney | Camera Operator |
| Bob Jones | Sound Recordist |
| Alban Streeter | Sound Editor |
| Alan Corder | Sound Editor |
| Jimmy Evans | Makeup Artist |
| Laurel Staffell | Wardrobe Designer |
| H.P. Lovecraft | Short Story |
| Philip Martell | Music Director |
