Gene Barry

Clayton Forrester

Ann Robinson

Sylvia Van Buren

Lewis Martin

Matthew Collins

Les Tremayne

General Mann

Frank Kreig

Fiddler Hawkins (uncredited)

Vernon Rich

Ralph Heffner

Sandro Giglio

Dr. Bilderbeck

Ann Codee

Dr. Duprey (uncredited)

Robert Cornthwaite

Dr. Pryor

Cedric Hardwicke

Commentary (voice)

Houseley Stevenson Jr.

General Mann's Aide

William Phipps

Wash Perry

Jack Kruschen

Salvatore

Paul Birch

Alonzo Hogue (uncredited)

Paul Frees

Second Radio Reporter / Opening Announcer