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)

Edward Colmans

Spanish Priest (uncredited)

Russ Conway

Rev. Bethany (uncredited)

Pierre Cressoy

Frenchman (uncredited)

Ralph Dumke

Buck Monahan (uncredited)

Al Ferguson

Police Chief (uncredited)

Charles Gemora

Martian (uncredited)

Ned Glass

Well-Dressed Looter (uncredited)

Fred Graham

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)

Michael Jeffers

Worker Listening to Radio (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)

George Magrill

Traffic Cop (uncredited)

Joel Marston

Military Policeman in Jeep (uncredited)

John Maxwell

Doctor (uncredited)

David McMahon

Minister, First Church (uncredited)

Lee Miller

Reporter (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)

David Sharpe

Looter (uncredited)

Teru Shimada

Japanese Diplomat (uncredited)

Bert Stevens

Man in Church (uncredited)

Jack Stoney

Looter (uncredited)

Arthur Tovey

Party Guest (uncredited)

Dale Van Sickel

Looter (uncredited)

Dorothy Vernon

Elderly Woman at Square Dance (uncredited)

Anthony Warde

Military Police Driver (uncredited)