Gary Lockwood

as Dr. Frank Poole

as Lt. Cmdr. Gary Mitchell

as Grant

as Sam Mercer

as John Hopper

as Nicholas Varsi

as Allen 'Toots' Tuttle

as Claude

as Gang Member (uncredited)

as Kelsey

as Davey Carroll

as Sgt. Meider

as Jim Stark

as James Figg

as Charley Belasco

as DEA Agent Twill

as Earl

as George Matthews

as John Praiser

as Danny Burke

as Sir George

as William

as Cliff Macy

as Howard Lee

as Dr. Owen Denny

as Ben Stone

as Ben Sillman

as Tony Ferris

as Ernie

as Owen Russell

as Gary

as Jordan Evanhower

as Russian basketball player

as David Seville

as Dr. Carl Webson

as Frank Lassiter

as Rossiter

as Self

as Walter Lucas

as Leroy Hastings

as Ben

as Self

as Clint Bethard

as John DeLacey

as Harley Moon

as Major Douglas

as Sheriff Earl Baker

as Frank Connery

as Lt. William 'Bill' Rice

as Stan Gallagher

as Capt. Kramer

as Frank Clinger

as Eliot Travis

as Dr. David Becker

as Fred Barker

as Dave Cully

as Bo