Jonathan Haze as Seymour Krelborn

Jackie Joseph as Audrey Fulquard

Mel Welles as Gravis Mushnick

Dick Miller as Burson Fouch

Myrtle Vail as Winifred Krelborn

Karyn Kupcinet as Shirley

Toby Michaels as Teenage Girl

Leola Wendorff as Siddie Shiva

Lynn Storey as Mrs. Hortense Feuchtwanger

Wally Campo as Det. Sgt. Joe Fink / Narrator

Jack Nicholson as Wilbur Force

Jack Warford as Det. Frank Stoolie

Meri Welles as Leonora Clyde

John Herman Shaner as Dr. Phoebus Farb

Dodie Drake as Waitress

Charles B. Griffith as Screaming Patient/ Audrey Junior (voice) / Burglar (uncredited)

Frank Mills as Man in Crowd Outside Shop (uncredited)

Jack Griffin as Drunk (uncredited)

Robert Coogan as Tramp (uncredited)