 | Vincent Price als Simon Cordier |
 | Nancy Kovack als Odette Mallotte |
 | Chris Warfield als Paul Duclasse |
 | Elaine Devry als Jeanne D'Arville |
 | Ian Wolfe als Pierre |
 | Stephen Roberts als Captain Robert Rennedon |
 | Lewis Martin als Father Raymonde |
| Mary Adams als Louise |
 | Nelson Olmsted als Dr. Borman |
 | Don Brodie als Marcel |
 | Harvey Stephens als Louis Girot |
 | Joseph Ruskin als The Horla (voice) |
| Robert E. Kent | Screenplay |
| Reginald Le Borg | Director |
| Robert E. Kent | Producer |
| Daniel Haller | Art Direction |
| Guy de Maupassant | Story |
| Richard LaSalle | Original Music Composer |
| Marjorie Corso | Costume Design |
| Victor A. Gangelin | Set Decoration |
| Jane Ficker | Script Supervisor |
| Grant Whytock | Editor |
| Ellis W. Carter | Director of Photography |
| Joseph Small | Production Manager |
| Al Westen | Assistant Director |
| Ted Coodley | Makeup Artist |
| Carmen Dirigo | Hairstylist |
| Edward Small | Producer |
| Alfred R. Bird | Sound Effects Editor |
| Edna Bullock | Music Editor |
| Norman Breedlove | Special Effects |
| Irving W. Sindler | Property Master |
| Ralph Butler | Sound |
| Lowell Grant | Sculptor |
