 | Gig Young als Mike Kelton |
 | Carol Lynley als Susannah Whately Kelton / Sarah |
 | Oliver Reed als Ethan |
 | Flora Robson als Aunt Agatha |
 | Judith Arthy als Emma |
 | Ann Bell als Mary Whately, Susannah's Mother |
 | William Devlin als Zebulon Whately |
 | Charles Lloyd Pack als Barge Master |
 | Bernard Kay als Tait |
| David Greene | Director |
| Ken Hodges | Director of Photography |
| Caroline Mott | Costume Design |
| H.P. Lovecraft | Book |
| August Derleth | Book |
| D.B. Ledrov | Writer |
| Nat Tanchuck | Writer |
| Jack Harding | Original Music Composer |
| Hylan Booker | Costume Designer |
| Frederick Yale | Casting |
| Harry Frampton | Makeup Artist |
| Alexander Jacobs | Associate Producer |
| Basil Kirchin | Original Music Composer |
| Brian Eatwell | Art Direction |
| Phillip Hazleton | Producer |
| Kevin Sutton | Sound Mixer |
| Brian Smedley-Aston | Editor |
| Don Challis | Sound Editor |
| Herbert Smith | Camera Operator |
| Eileen Warwick | Hairdresser |
| Bernard Schwartz | Executive Producer |
