Gene Barry

Dr. Clayton Forrester

Ann Robinson

Sylvia Van Buren

Lewis Martin

Pastor Dr. Matthew Collins

Les Tremayne

Maj. Gen. Mann

Frank Kreig

Fiddler Hawkins (uncredited)

Vernon Rich

Col. Ralph Heffner

Sandro Giglio

Dr. Bilderbeck

Ann Codee

Dr. Duprey (uncredited)

Robert Cornthwaite

Dr. Pryor (as Bob Cornthwaite)

Cedric Hardwicke

Commentary (voice) (as Sir Cedric Hardwicke)

William Phipps

Wash Perry (as Bill Phipps)

Jack Kruschen

Salvatore

Paul Birch

Alonzo Hogue (uncredited)

Paul Frees

Second Radio Reporter / Opening Announcer

Henry Brandon

Cop at Crash Site

Peter Adams

Pine Summit Fire Watcher (uncredited)

Eric Alden

Man (uncredited)

Edgar Barrier

Prof. McPherson (uncredited)

Russ Bender

Dr. Carmichael (uncredited)

Chet Brandenburg

Man in Church (uncredited)

George Bruggeman

Soldier (uncredited)

Nora Bush

Woman in Church (uncredited)

Mushy Callahan

Burning Soldier at Pit (uncredited)

Dick Cherney

Looter (uncredited)

Edward Colmans

Spanish Priest (uncredited)

James Conaty

Man at Pacific Institute of Science and Technology (uncredited)

Russ Conway

Rev. Bethany (uncredited)

Pierre Cressoy

Frenchman (uncredited)

Oliver Cross

Scientist (uncredited)

Ralph Dumke

Buck Monahan (uncredited)

Ned Glass

Well-Dressed Looter (uncredited)

Jack Gordon

Man in Church (uncredited)

Fred Graham

Looter (uncredited)

Joe Gray

Looter (uncredited)

Herman Hack

Worker Listening to Radio (uncredited)

Nancy Hale

Young Wife (uncredited)

Ted Hecht

KGEB Reporter (uncredited)

Douglas Henderson

Staff Sergeant (uncredited)

Gertrude Hoffmann

Elderly News Vendor (uncredited)

Tex Holden

Man in Church (uncredited)

Jimmie Horan

Party Guest (uncredited)

Dick Johnstone

Man in Church (uncredited)

Carolyn Jones

Blonde Party Guest (uncredited)

Ivan Lebedeff

Dr. Gratzman (uncredited)

Freeman Lusk

Secretary of Defense (uncredited)

Herbert Lytton

Chief of Staff (uncredited)

Wilbur Mack

Official (uncredited)

Sydney Mason

Fire Chief, Crew #3 (uncredited)

John Maxwell

Doctor (uncredited)

Mathew McCue

Man in Church (uncredited)

David McMahon

Minister, First Church (uncredited)

William Meader

P.E. Official (uncredited)

Lee Miller

Reporter (uncredited)

Ralph Montgomery

Los Angeles Red Cross Official (uncredited)

Alvy Moore

Zippy (uncredited)

Bob Morgan

Injured Civil Defense Worker (uncredited)

Charles Morton

Worker Listening to Radio (uncredited)

George Nardelli

Military Officer (uncredited)

George Pal

Bum #1 Listening to Radio (uncredited)

Robert Rockwell

Forest Ranger at Crash Site (uncredited)

Walter Sande

Sheriff Bogany (uncredited)

James Seay

Air Force Bomber Pilot (uncredited)

Teru Shimada

Japanese Diplomat (uncredited)

Bobby Somers

Deputy at Crash Site (uncredited)

Bert Stevens

Man in Church (uncredited)

Arthur Tovey

Party Guest (uncredited)

Dale Van Sickel

Looter (uncredited)

Chalky Williams

Worker Listening to Radio (uncredited)