George Maharis
Lee Barrett
Richard Basehart
Dr. Gregor Hoffman
Anne Francis
Ann Williams
Dana Andrews
Gen. Williams
John Larkin
Dr. Leonard Michaelson
Richard Bull
Eric Cavanaugh
Frank Sutton
Henchman Donald
Ed Asner
Henchman Veretti
Simon Oakland
Tasserly
John Anderson
Agent Reagan
John Clarke
Guard Lt. Raskin
Hari Rhodes
Guard Lt. Johnson
Martin Blaine
Martin
Henry Beckman
Dr. Baxter
Harry Lauter
Fake SDI Agent
James Hong
Dr. Yang
Russ Bender
Desk Guard Mason
Harold Gould
Dr. Ostrer (uncredited)
Lee Remick
Waitress
William Bryant
Lead Agent "X-Ray", drives car
James Doohan
Second Agent "X-Ray", scratches hand
Michael Barrier
Helicopter Pilot Henchman
Tol Avery
Detective Captain at Baseball Stadium
John Hubbard
Guard