Lloyd Bridges
Colonel Floyd Graham
Osa Massen
Dr. Lisa Van Horn
John Emery
Dr. Karl Eckstrom
Noah Beery Jr.
Major William Corrigan
Hugh O'Brian
Harry Chamberlain
Morris Ankrum
Dr. Ralph Fleming
Patrick Aherne
Reporter #1
Sherry Moreland
Martian girl
Tom Coleman
Reporter (uncredited)
James Conaty
Doctor Taking Lisa's Blood Pressure (uncredited)
Sam Harris
Reporter at Press Briefing (uncredited)
Judd Holdren
Reporter #3 (uncredited)
Stuart Holmes
Reporter (uncredited)
Barry Norton
Reporter (uncredited)
Cosmo Sardo
Reporter (uncredited)
Bert Stevens
Reporter (uncredited)