John F. Kennedy - US President
Adlai Stevenson - US Ambassador to UN
Nikita Khrushchev - Soviet Premier
U Thant - U.N. Secretary-General
Atty. Gen. Robert F. Kennedy
David Powers - Special Assistant to the President
Admiral's Aide
John McCone - Director CIA
Press Photographer
Theodore Sorensen - Special Counsel
Senator
Dean Acheson - Former Secretary of State
David Ormsby-Gore - British Ambassador to U.S.
Gen. Maxwell Taylor - Army Chief of Staff
Gen. David M. Shoup - USMC Commandant
Robert McNamara - Secretary of Defense
Russian Presidium Member (as Gene Elman)
Gen. Charles De Gaulle
Soviet Marshal
Congressman Charles A. Halleck
Dean Rusk - Secretary of State
Reporter
American General
Russian Presidium Member
Chief of the Presidium
W.E. Knox - President, Westinghouse International
Sen. Richard Russell
Valerian Zorin
John Scali - ABC Correspondent
Mrs. Evelyn Lincoln - President Kennedy's Secretary
Pierre Salinger - White House Press Secretary
Gen. Curtis LeMay, - Air Force Chief of Staff
Yefgani Yeftashanko
Sen. J. William Fulbright
Kenneth O'Donnell - Special Assistant to the President
Television Assistant
McGeorge Bundy - Special Assistant for National Security Affairs
Llewellyn Thompson - Former U.S. Ambassador to the Soviet Union
Ambassador Anatoly Dobrynin
Andrei Gromyko - Soviet Foreign Minister
C. Douglas Dillon - Secretary of the Treasury
George Ball - Undersecretary of State
Waiter
Adm. George W. Anderson Jr. - Chief of Naval Operations
Soviet Stenographer
Cuban Delegate (as Jay Vallera)
Civillian Aide
Alexander Fomin - KGB Agent
Narrator (uncredited)