Gene Barry character Dr. Clayton Forrester
Ann Robinson character Sylvia Van Buren
Lewis Martin character Pastor Dr. Matthew Collins
Les Tremayne character Maj. Gen. Mann
Frank Kreig character Fiddler Hawkins (uncredited)
Vernon Rich character Col. Ralph Heffner
Sandro Giglio character Dr. Bilderbeck
Ann Codee character Dr. Duprey (uncredited)
Robert Cornthwaite character Dr. Pryor (as Bob Cornthwaite)
Cedric Hardwicke character Commentary (voice) (as Sir Cedric Hardwicke)
Houseley Stevenson Jr. character Gen. Mann's Aide (as Housely Stevenson Jr.)
William Phipps character Wash Perry (as Bill Phipps)
Jack Kruschen character Salvatore
Paul Birch character Alonzo Hogue (uncredited)
Paul Frees character Second Radio Reporter / Opening Announcer
Henry Brandon character Cop at Crash Site
Peter Adams character Pine Summit Fire Watcher (uncredited)
Eric Alden character Man (uncredited)
Hugh Allen character Brigadier General (uncredited)
Ruth Barnell character Mother (uncredited)
Edgar Barrier character Prof. McPherson (uncredited)
Russ Bender character Dr. Carmichael (uncredited)
Oscar Blank character Man in Church (uncredited)
Nick Borgani character Man in Church (uncredited)
Hazel Boyne character Screaming Woman (uncredited)
Chet Brandenburg character Man in Church (uncredited)
George Bruggeman character Soldier (uncredited)
Nora Bush character Woman in Church (uncredited)
Tony Butala character Boy in Final Church (uncredited)
Mushy Callahan character Burning Soldier at Pit (uncredited)
Dick Cherney character Looter (uncredited)
Edward Colmans character Spanish Priest (uncredited)
James Conaty character Man at Pacific Institute of Science and Technology (uncredited)
Russ Conway character Rev. Bethany (uncredited)
Martin Coulter character Marine Sergeant (uncredited)
Vittorio Cramer character First Radio Reporter (uncredited)
Pierre Cressoy character Frenchman (uncredited)
Oliver Cross character Scientist (uncredited)
Jane Crowley character Woman in Church (uncredited)
Jim Davies character Marine Commanding Officer (uncredited)
Helen Dickson character Woman in Church (uncredited)
Ralph Dumke character Buck Monahan (uncredited)
Jimmie Dundee character Civil Defense Official (uncredited)
Al Ferguson character Police Chief (uncredited)
Dick Fortune character Marine Captain (uncredited)
Alex Frazer character Dr. James (uncredited)
Frank Freeman Jr. character Bum #2 Listening to Radio (uncredited)
Slim Gaut character Radio Listener (uncredited)
Charles Gemora character Martian (uncredited)
Ned Glass character Well-Dressed Looter (uncredited)
Jack Gordon character Man in Church (uncredited)
Fred Graham character Looter (uncredited)
Joe Gray character Looter (uncredited)
Herman Hack character Worker Listening to Radio (uncredited)
Nancy Hale character Young Wife (uncredited)
Virginia Hall character Girl (uncredited)
Ted Hecht character KGEB Reporter (uncredited)
Douglas Henderson character Staff Sergeant (uncredited)
Gertrude Hoffmann character Elderly News Vendor (uncredited)
Tex Holden character Man in Church (uncredited)
Jimmie Horan character Party Guest (uncredited)
Patricia Iannone character Girl (uncredited)
Jerry James character Reporter (uncredited)
Michael Jeffers character Worker Listening to Radio (uncredited)
Dick Johnstone character Man in Church (uncredited)
Carolyn Jones character Blonde Party Guest (uncredited)
Don Kohler character Colonel (uncredited)
Ivan Lebedeff character Dr. Gratzman (uncredited)
Freeman Lusk character Secretary of Defense (uncredited)
Herbert Lytton character Chief of Staff (uncredited)
Wilbur Mack character Official (uncredited)
George Magrill character Traffic Cop (uncredited)
Mike Mahoney character Townsman (uncredited)
John Mansfield character Man (uncredited)
Joel Marston character Military Policeman in Jeep (uncredited)
Sydney Mason character Fire Chief, Crew #3 (uncredited)
John Maxwell character Doctor (uncredited)
Mathew McCue character Man in Church (uncredited)
David McMahon character Minister, First Church (uncredited)
William Meader character P.E. Official (uncredited)
Lee Miller character Reporter (uncredited)
Ralph Montgomery character Los Angeles Red Cross Official (uncredited)
Alvy Moore character Zippy (uncredited)
Bob Morgan character Injured Civil Defense Worker (uncredited)
Charles Morton character Worker Listening to Radio (uncredited)
George Nardelli character Military Officer (uncredited)
Stanley Orr character Marine Major (uncredited)
George Pal character Bum #1 Listening to Radio (uncredited)
Walter Richards character Reporter (uncredited)
Robert Rockwell character Forest Ranger at Crash Site (uncredited)
Walter Sande character Sheriff Bogany (uncredited)
James Seay character Air Force Bomber Pilot (uncredited)
Allen D. Sewall character Man in Church (uncredited)
Lucile Sewall character Woman in Church (uncredited)
Cora Shannon character Old Woman (uncredited)
David Sharpe character Looter (uncredited)
Teru Shimada character Japanese Diplomat (uncredited)
Reginald Lal Singh character Military Officer (uncredited)
Bobby Somers character Deputy at Crash Site (uncredited)
Bert Stevens character Man in Church (uncredited)
Charles Stewart character Marine Captain (uncredited)
Jack Stoney character Looter (uncredited)
Gus Taillon character Elderly Man (uncredited)
Morton C. Thompson character Reporter (uncredited)
Arthur Tovey character Party Guest (uncredited)
Dale van Sickel character Looter (uncredited)
Dorothy Vernon character Elderly Woman at Square Dance (uncredited)
Edward Wahrman character Cameraman (uncredited)
Anthony Warde character Military Police Driver (uncredited)
Bob Whitney character Military Officer (uncredited)
Chalky Williams character Worker Listening to Radio (uncredited)
Waldon Williams character Boy (uncredited)
Bud Wolfe character Rescuing Civil Defense Worker (uncredited)
Fred Zendar character Marine Lieutenant (uncredited)
