Hugh Marlowe
Dr. Russell A. Marvin
Joan Taylor
Carol Marvin
Donald Curtis
Maj. Huglin
Morris Ankrum
Brig. Gen. John Hanley
Thomas Browne Henry
Vice Adm. Enright
Grandon Rhodes
Gen. Edmunds
John Zaremba
Prof. Kanter
Paul Frees
Alien (voice)
Frank Wilcox
Alfred Cassidy
Sydney Mason
Frank the garage man
Larry J. Blake
Motorcycle cop
Bert Stevens
Air Intelligence Command Officer
Forbes Murray
Military Officer at Experiment
Arthur Tovey
Officer/Civilian at Military Conference
