Bob Newhart as Bernard (voice)

Eva Gabor as Miss Bianca (voice)

Geraldine Page as Madame Medusa (voice)

Joe Flynn as Mr. Snoops (voice)

Jeanette Nolan as Ellie Mae (voice)

Pat Buttram as Luke (voice)

Jim Jordan as Orville (voice)

John McIntire as Rufus (voice)

Michelle Stacy as Penny (voice)

Bernard Fox as The Chairman (voice)

Larry Clemmons as Gramps (voice)

James MacDonald as Evinrude / Brutus / Nero (voice)

George Lindsey as Rabbit (voice)

Bill McMillian as TV Announcer (voice)

Dub Taylor as Digger (voice)

John Fiedler as Owl (voice)

Robie Lester as Miss Bianca (singing voice, uncredited)

Peter Renaday as American Deligate (voice) (uncredited)