Cast of Them!

24 credited, in billing order.

James Whitmore
James Whitmoreas Sgt. Ben Peterson
James Arness
James Arnessas FBI Agent Robert Graham
Joan Weldon
Joan Weldonas Dr. Pat Medford
Edmund Gwenn
Edmund Gwennas Dr. Harold Medford
Onslow Stevens
Onslow Stevensas Brig. Gen. Robert O'Brien
Sean McClory
Sean McCloryas Maj. Kibbee
Sandy Descher
Sandy Descheras The Ellinson Girl
Chris Drake
Chris Drakeas Trooper Ed Blackburn
Don Shelton
Don Sheltonas Trooper Capt. Fred Edwards
Fess Parker
Fess Parkeras Alan Crotty
Mary Alan Hokanson
Mary Alan Hokansonas Mrs. Lodge
Olin Howland
Olin Howlandas Jensen
William Schallert
William Schallertas Ambulance Attendant
Ann Doran
Ann Doranas Child Psychiatrist
Dub Taylor
Dub Tayloras Railroad Yard Watchman
Leonard Nimoy
Leonard Nimoyas Army Sergeant
Richard Deacon
Richard Deaconas Bald Reporter at L.A. News Conference
Forbes Murray
Forbes Murrayas Government Official
Kenner G. Kemp
Kenner G. Kempas Trooper #2
Charles Perry
Charles Perryas Soldier
Dorothy Green
Dorothy Greenas Matron
Willis Bouchey
Willis Boucheyas Official at D.C. Meeting
Mary Lou Holloway
Mary Lou Hollowayas Blonde at Police Station
Dick York
Dick Yorkas Teenager in Police Station

Crew