Roddy McDowall
Cornelius
Acting
Kim Hunter
Dr. Zira
Acting
Bradford Dillman
Dr. Lewis Dixon
Acting
Natalie Trundy
Dr. Stephanie 'Stevie' Branton
Acting
Eric Braeden
Dr. Otto Hasslein
Acting
William Windom
The President
Acting
Sal Mineo
Dr. Milo
Acting
Albert Salmi
E-1
Acting
Jason Evers
E-2
Acting
John Randolph
Committee Chairman
Acting
Harry Lauter
General Winthrop
Acting
M. Emmet Walsh
Aide
Acting
Roy Glenn
Lawyer (as Roy E. Glenn Sr.)
Acting
Peter Forster
Cardinal
Acting
Norman Burton
Army Officer
Acting
William Woodson
Naval Officer
Acting
Tom Lowell
Orderly
Acting
Gene Whittington
Marine Captain
Acting
Donald Elson
Curator
Acting
Bill Bonds
TV Newscaster
Acting
Army Archerd
Referee
Acting
James Bacon
General Faulkner
Acting
Ricardo Montalban
Armando
Acting
John Alderman
Marine Corporal (uncredited)
Acting
Alan Baxter
General (uncredited)
Acting
Jack Berle
Secretary of State (uncredited)
Acting
Paul Bradley
Official at Briefing (uncredited)
Acting
Karl Bruck
German Newscaster (uncredited)
Acting
Sam Chew Jr.
Undetermined (uncredited)
Acting
Robert Cole
Reporter (uncredited)
Acting
Walker Edmiston
Talking Baby Chimp (uncredited) (voice)
Acting
Sig Frohlich
Spectator (uncredited)
Acting
James W. Gavin
Helicopter Pilot (uncredited)
Acting
George Golden
Official at Briefing (uncredited)
Acting
James Gonzalez
Official at Briefing (uncredited)
Acting
Joe Gray
Bodyguard (uncredited)
Acting
Bob Harks
Aide (uncredited)
Acting
Linda Harrison
Nova (archive footage) (uncredited)
Acting
Elizabeth Harrower
Reporter at Hotel (uncredited)
Acting
Shep Houghton
Bystander (uncredited)
Acting
Joseph La Cava
Waiter (uncredited)
Acting
Robert Nichols
Reporter (uncredited)
Acting
Ron Pinkard
Undetermined (uncredited)
Acting
Janos Prohaska
Heloise (uncredited)
Acting
Tony Regan
Reporter at Hotel (uncredited)
Acting
Stephen Roberts
Gen. Brody (uncredited)
Acting
Hank Robinson
Reporter (uncredited)
Acting
James B. Sikking
Control Room Officer (uncredited)
Acting
Jack Slate
Reporter (uncredited)
Acting
Arthur Tovey
Official at Briefing (uncredited)
Acting
William Tregoe
Hotel Receptionist (uncredited)
Acting
William Beckley
British News Anchor (uncredited)
Acting