•
James Stewart as Medical Corps Pvt. O'Hara •
John Miltern as Major
Walter Reed •
Edward Acuff as Pvt. McClelland •
Wylie Adams as Kraemer, as a Commissary Sergeant and as a member from the Rockefeller Foundation • Jack Carr as Chambang, a Native Laboratory Assistant •
Eduardo Ciannelli as
Aristides Agramonte, a Member of the American Yellow Fever Commission •
Francis Compton as a Major of the Royal Air Force • Charles Gerard as Adrian Stokes, of the West African Yellow Fever Commission, Rocke •
Lloyd Gough as a Laboratory Assistant and as an Army Chaplain •
Harold Hoffat as Roger P. Ames, an Asst. Surgeon •
Colin Hunter (actor) as an Official of the Kenya Colony Government •
Bernard Jukes as a Laboratory Assistant •
Whitford Kane as Dr.
Carlos Finlay •
Robert Keith as
Jesse W. Lazear, a member of the American Yellow Fever Commission •
Geoffrey Kerr as Stackpoole •
Sam Levene as Pvt. Busch •
Richie Ling as Colonel Tory of the Marine Hospital Corps •
Barton MacLane as
James Carroll, a member of the American Yellow Fever Commission •
Myron McCormick as Pvt. Brinkerhof •
Millard Mitchell as Pvt. William H. Dean •
Jock Munro as a Laboratory Assistant • George Nash as Major
William Crawford Gorgas •
Robert Shayne as Harkness and as Major Cartwright •
Frank Stringfellow as an Orderly •
Clyde Walters as an Orderly • Katherine Wilson as Miss Blake, a Special Nurse in Charge of the Yellow Fever Ward ==Revivals==