Richard Denning as Dr. Chet Walker

S. John Launer as Capt. Dave Harris

Michael Granger as Frank Buchanan

Gregory Gaye as Dr. Wilhelm Steigg

Angela Stevens as Joyce Walker

Linda Bennett as Penny Walker

Charles Evans as Chief Camden

Tristram Coffin as Dist. Atty. MacGraw

Pierre Watkin as Mayor Bremer

Harry Lauter as Reporter #1

Larry J. Blake as Reporter #2

Paul Hoffman as Tom Dunn (uncredited)

Nelson Leigh as Dr. Kenneth C. Norton (uncredited)

Edward Coch as Jason Franchot (uncredited)

Lane Chandler as Gen. Saunders (uncredited)

Don C. Harvey as Lester Banning (uncredited)

Richard H. Cutting as Dick Cutting, Radio Broadcaster (uncredited)

Paul Bradley as Gambling Casino Employee (uncredited)

Karl 'Killer' Davis as Willard Pearce (uncredited)

Terry Frost as Tom, Policeman (uncredited)

Cap Somers as Policeman (uncredited)

Tyler McVey as Police Officer (uncredited)

Eddie Foster as Bartender (uncredited)

Bill Clark as Policeman (uncredited)

Chuck Hicks as Pilot (uncredited)

Dick Crockett as Creature Who Calls Camden (uncredited)

George Bruggeman as Creature (uncredited)

Charles Horvath as Creature (uncredited)

Boyd 'Red' Morgan as Creature (uncredited)

Michael Ross as Creature Vernon Dunn (uncredited)