- George Peppard
- Pete
- Mary Tyler Moore
- Liz
- Don Stroud
- Barney
- Susan Saint James
- Aida
- Dom DeLuise
- J. Gardner Monroe
- Nathaniel Frey
- Conrad
- John McMartin
- The Mayor
- Charles Lane
- Dr. Shapiro
- Jeanne Arnold
- Gertrude
- George Furth
- Murgatroyd
- Morty Gunty
- Sgt. Gunty
- Joe Ponazecki
- Officer Ponazecki
- Frank Campanella
- Capt. Wallace
- Thelma Ritter
- Mrs. Schwartz
- Tom Ahearne
- Brady
- Hy Anzell
- (uncredited)
- Ralph Bell
- Dr. Langley
- Robert Bond
- Mayor's Aide
- Richard Buck
- Board Member
- Franklin Cover
- Medical Expert
- Joel Crothers
- Board Member
- Hal K. Dawson
- Harris
- Angus Duncan
- Board Member
- Joey Faye
- Zookeeper
- Conard Fowkes
- Board Member
- Hugh Franklin
- Park Commissioner Williams
- Arny Freeman
- 1st Mate
- Peter Gumeny
- (uncredited)
- Moses Gunn
- (uncredited)
- Albert Henderson
- (uncredited)
- Donald Hotten
- Sam
- Bob Kaliban
- Junior Executive
- Lincoln Kilpatrick
- Wilson
- Jára Kohout
- Soviet Delegate
- Mina Kolb
- Woman in Pad
- Adeline Leonard Seakwood
- Lab Technician
- Ira Lewis
- (uncredited)
- Cleavon Little
- Phil
- Salem Ludwig
- Witter
- Lou Martini Jr.
- Crying Boy At City Hall
- Eda Reiss Merin
- (uncredited)
- Barbara Minkus
- Harriet
- Robert Moore
- Board Member
- James Noble
- Board Member
- Martin O'Hara
- T.V. Newscaster
- George Petrie
- Bolton
- Nat Polen
- (uncredited)
- Victoria Racimo
- Woman in Pad
- Tom Rosqui
- Radio Cop
- John P. Ryan
- Roger
- Marc Seaton
- Man in Pad
- Gillian Spencer
- The Sack
- George Sperdakos
- Crewman
- Carmine Stippo
- Charlie
- Peter Turgeon
- Security Expert
- Kay Turner
- Woman in Pad
- Luis Van Rooten
- Dr. Fowler
- Titos Vandis
- Captain Narcopolis
- Ned Wertimer
- Marshall legal aide
- Emily Yancy
- Sybil
- Louis Zorich
- (uncredited)
