Bud Abbott as Slim

Lou Costello as Tubby

Boris Karloff as Dr. Henry Jekyll / Mr. Hyde

Craig Stevens as Bruce Adams

Helen Westcott as Vicky Edwards

Reginald Denny as Inspector

John Dierkes as Batley

Eddie Parker as Mr. Hyde (uncredited)

Patti McKaye as Can-can dancer

Betty Tyler as Can-can dancer

Lucille Lamarr as Can-can dancer

Dante De Paolo as Specialty dancer

Carmen De Lavallade as Javanese dancer

Maisay Kawasuma as Javanese dancer

Henry Coden as Javanese actor

Marjorie Bennett as Militant woman

Isabelle Dwan as Mrs. Penprase

James Fairfax as Mr. Penprase

Harry Wilson as Man Asking for Match

Harry Cording as Rough Character in the Park