Obsada:

• Paul Newman Gen. Leslie R. Groves
• Dwight Schultz J. Robert Oppenheimer
• Bonnie Bedelia Kitty Oppenheimer
• John Cusack Michael Merriman
• Laura Dern Kathleen Robinson
• Ron Frazier Peter de Silva
• John C. McGinley Capt. Richard Schoenfield, MD
• Natasha Richardson Jean Tatlock
• Ron Vawter Jamie Latrobe
• Michael Brockman William 'Deke' Parsons
• Del Close Dr. Kenneth Whiteside
• John Considine Robert Tuckson
• Allan Corduner Franz Goethe
• Joe D'Angerio Seth Neddermeyer
• Jon DeVries Johnny Mount
• James Eckhouse Robert Harper
• Todd Field Robert Wilson
• Mary Pat Gleason Dora Welsh
• Clark Gregg Douglas Panton
• Péter Halász George Kistiakowsky
• Gerald Hiken Leo Szilard
• Arthur Holden Oak Ridge Doctor
• Ed Lauter Whitney Ashbridge
• Donald MacKechnie James Tuck
• Madison Mason Boris Pash
• Krzysztof Pieczynski Otto Frisch
• Don Pugsley Sgt. Bronston, Groves' Orderly
• Logan Ramsey Brehon Somervell
• Fred Dalton Thompson Maj. Gen. Melrose Hayden Barry
• Jim True-Frost Donald Hornig
• Barry Yourgrau Edward Teller
• Marek Alboszta Scientist
• Steven Baigelman Dr. Avenell
• Frank Benettieri Jr. Messenger
• Roger Cubicciotti Frank Oppenheimer
• Franco Cutietta Enrico Fermi
• Robert Peter Gale Dr. Louis Hempelman
• Wesley Harrison Peter Oppenheimer
• Brent Harrison Peter Oppenheimer
• Tom McFarlane Scientist
• David C. Parnes Raincoat Man
• Allen Poirson Harold McDonald
• David Politzer Robert Serber
• Bill Rubenstein N.Y. Times Reporter
• Ken Strausbaugh Observation Officer
• Walter Sullivan Secretary of War Henry Stimson
• Brian Wandell Dennis Talmudge
• John Williams Mack Stoddard
• Walker Edmiston
• Matthew Faison
• Stan Jones
• Alan Oppenheimer