Keir Dullea

Dr. David Bowman

Gary Lockwood

Dr. Frank Poole

William Sylvester

Dr. Heywood Floyd

Douglas Rain

HAL 9000 (voice)

Daniel Richter

Moonwatcher

Leonard Rossiter

Dr. Andrei Smyslov

Margaret Tyzack

Elena

Robert Beatty

Dr. Ralph Halvorsen

Ed Bishop

Aries-1B Lunar Shuttle Captain

Glenn Beck

Astronaut

Alan Gifford

Poole's Father

Ann Gillis

Poole's Mother

Edwina Carroll

Aries-1B Stewardess

Penny Brahms

Stewardess

David Charkham

Ape

Maggie London

Hostess in Elevator (uncredited)

Chela Matthison

Receptionist (uncredited)

Vivian Kubrick

Floyd's Daughter (uncredited)

Kenneth Kendall

BBC-12 Announcer (uncredited)

Kevin Scott

Miller (uncredited)

John Swindells

TMA-1 Site Technician #1 (uncredited)

Stanley Kubrick

Astronaut Breathing (voice) (uncredited)