 | Peter Sellers als Dr. Albert T. Hopfnegal |
 | Jo Ann Pflug als Alice Gilligan |
 | Rick Lenz als Lester Hammond |
 | Harold Gould als Dr. Herman Zerny |
 | Eve Bruce als Nurse Lamarr |
 | J. Edward McKinley als George Leffingwell, Hospital Commissioner |
 | Hope Summers als Nurse Throttle |
 | Pat Morita als Harry Nishimoto |
 | Brett Halsey als Dr. Paolo Quagliomo |
 | Kathleen Freeman als Mrs. Manzzini |
 | Norman Alden als Katzen |
 | William Elliott als Oscar |
 | Uschi Digard als Girl at Party (uncredited) |
| Josef Shaftel | Executive Producer |
| Susan Perkins | Production Office Assistant |
| John McDonald | Boom Operator |
| Rod Amateau | Director |
| Tony Sarzi-Braga | Production Design |
| Jack Morrisey | Art Department Coordinator |
| Dave Smith | Construction Foreman |
| Duane Toler | Script Supervisor |
| Frank Tauss | Costume Design |
| Frank Tucker | Location Manager |
| William Schwartz | Producer |
| Rod Amateau | Producer |
| Rosalee Berman | Producer |
| Budd Robinson | Novel |
| Biff Elliot | Dialogue |
| John Speak | Sound mixer |
| Keith Allison | Music |
| Del Acevedo | Makeup Artist |
| Rod Amateau | Novel |
| John Marwick | Producer |
| David Hawks | Production Manager |
| "Jockey" Liebgold | Property Master |
| Brick Marquard | Director of Photography |
| William Flannigan | Production Office Assistant |
| Bonnie Godfrey | Casting |
| Michael D. Haller | Art Direction |
| Frank Bueno | Producer |
| William Lasky | Assistant Director |
