- Virginia Christine - Julie Hollister
- Francis Lederer - Brauer
- Lester Matthews - Colonel Brookston
- Kenneth Tobey - Colonel Pete Kellogg
- Denver Pyle - Roger Woodson
- John Doucette - Capt. John Benson
- Richard Davies - Werner
- James Best - Webb
- Florence Marly - Marie Savit
- Richard Webb - James Foster
- Eric Pohlmann - Drigo
- William Henry - Herb Goodwin
- Arlene Martel - Maria
- Reginald Gardiner - Ernest Farrington
- Jim Bannon - Colonel Patterson
- Judith Evelyn - Clara Koller
- Bill Quinn - Col. Barrett Cole
- Alex Gerry - Barnes
- Myron Healey - Lister
- John Banner - Prosecutor Hoxa
- Abraham Sofaer - Fadhil
- Peter Whitney - Edwin Getty
- Jack Kruschen - Ruchef
- Ruth Terry - Sally Anderson
- Angela Greene - Hazel Shaw
- Jeanne Baird - Nina
- Olan Soule - Hotchkiss
- Ferdy Mayne - General Racz
- Joe Maross - Wayne Hollister
- John Wengraf - Von Elm
- Joseph Marievsky - Alexis Shtaravna
- Tom McKee - Collins
- Peter Coe - Lieutenant Tarkhanov
- Melinda Byron - Janet Kellogg
- Douglas Evans - Kincaid
- Linda Leighton - Leona
- John McNamara - Ingram
- Sam Buffington - Horne
- Bek Nelson - Kitty
- James Todd - Clarke
- Stewart Bradley - Sam Lombardi
- John Damler - Dan Radford
- Ruth Lee - Mrs. Gates
- William Bryant - Capt. Peter Shiller
- Ralph Clanton - Ed Bailey
- Robert Knapp - Fred Lang
- Walter Maslow - Salvatori
- Dick Rich - Martin
- Jacques Aubuchon - Shulnik
- Jacques Aubuchon - Charlie Meyers
- Gil Frye - Selim
- Francis De Sales - Commander Rogers
- Marya Stevens - Rakya Ahmed
- Richard Flato - Serko
- Keith Richards - Andrew Fleming
- George Keymas - Aman
- Ziva Rodann - Jessica Tabor
- John Sutton - Shaw
- Sheldon Lawrence - Blake Adams
- Carl Duering - Rienk
- Jeanette Sterke - Sarah Fletcher
- Gabriel Curtiz - Russian Scientist
- Marc Snow - Captain
- Kathleen O'Malley - Sue-Ellen
- Samuel Gallu
Carl Duering hace el papel de Rienk.
Jack Kruschen interpreta a Ruchef en la serie.
Bruce Gordon interpreta a Commander Matson en la serie.
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