James Daly
/ Sergeant Pat Boyle / A cartoonist / Jim Briscoe / Bill Tanner / Professor Amo...

Charlton Heston
/ Commander Schneider / Col. / Dr. Michael Knowle / Merton Densher / James Otis...

John Forsythe
/ Capt. Sam MacKenzie / Pete Maynard / Judd / James Rexham / Marv Payne / Maj. ...

John Cannon
Self - Announcer (voice)

Everett Sloane
/ Korolenko / Mike Hudson / Giovanni / Jonah Silver / Walter Winkworth / Aaron ...

Richard Kiley
/ Merrick / Calvin / Ralph Johnson / Fred Baxter / Joe / Jim Colton / Richard B...

Leslie Nielsen
/ Dr. Roger Waring / Karl / Edmund / Tallman / Mac / Chris Jackson / Dr. Claybo...

Betsy Palmer
Ann Meade / / Ellen Morrison / Mimi / Dony Waller / Edith Olmstead / Maureen Dr...

Berry Kroeger
Mr. Lawrence / Sir Sagramor / Rembrandt Van Rijn / / Baron Tito Belcredi / Caia...

Shepperd Strudwick
/ Senator Greet / Nordlund / Hal Manning / Mac Taylor / Cassius

Vaughn Taylor
Mr. Racknall / / Casca / Prof. Henry Lempkin / Admiral Luetjens / Doc / Billy /...

Harry Townes
/ Peter Hartley / Mr. Hager / Eliot Nelson / Mr.Rogers / Outarist / Karl Weber

Nina Foch
Barbara / Carrie Brown Huddleston / Melissa Turner / Fran / Joyce / / Lee Fouch...

E.G. Marshall
/ Everett Metcalf / Aaron Kinney / George Banks / Harry Mork / Dr. Shratt

Bramwell Fletcher
/ Governor Bell / Mr. Wynteringham / Dr. Alderton

Hildy Parks
Fran / Maggie Troy / Doris Anderson / Avery Dow / Judy McDermott / Mabel Prentic...

Charles Korvin
Philip Hausman / / Gastman / Francis / El Cameron / Julian Wilder / Paul Collin...

Skip Homeier
Carl Green / The Boy / Capt. Gene Lipton / Peter Shea / Theodore Jr. / Dickie Ro...

James Gregory
James Metcalf / Mr. Bales / George Monzo / Mr. Black / Private Alan Pomeroy / Co...

Edward Andrews
C. Elliot Friday / Fistar Marrock / Nils / Forest / Henry Horne / Parker /