Jack Lemmon as Mel Edison

Anne Bancroft as Edna Edison

Gene Saks as Harry Edison

Elizabeth Wilson as Pauline

Florence Stanley as Pearl

Maxine Stuart as Belle

Ed Peck as Man Upstairs

Gene Blakely as Charlie

Ivor Francis as Psychiatrist

Stack Pierce as Detective

Patricia Marshall as Woman Upstairs

Dee Carroll as Helen

Ketty Lester as Unemployment Clerk

M. Emmet Walsh as Doorman

F. Murray Abraham as Taxi Driver

James McCallion as Mr. Cooperman

Fat Thomas as Bus Driver

Arlen Stuart as Elevator Passenger

Sylvester Stallone as Youth in Park

Alan DeWitt as Wayne Morgan

Harry Ray as Man with Dog

Lonnie Burr as Man on Street (uncredited)

Eddie Garrett as Elevator Passenger (uncredited)

Ben Lautman as NYU Student (uncredited)

Dave Michaels as Radio Newscaster (voice) (uncredited)

Gary Owens as Radio Newscaster (voice) (uncredited)

John Ritter as Elevator Passenger (uncredited)

Cosmo Sardo as Subway Passenger (uncredited)

Norman Stevans as Elevator Passenger (uncredited)

Joe Turkel as Man Upstairs (voice) (uncredited)