It examines how the military Brazilian evaluated the Chaco War (1932-1935) between Paraguay and Bolivia, from official reports and analysis on the state limit peak of the conflict. Goal is to propose that this view is informed by the character of geopolitical doctrines that have been consolidated in the country throughout the 1920s, finding definite contribution to the work of Mario Travassos, at the beginning of the next de-cade. The traditional rivalry with Argentina over the strategic supremacy in South America was updated so the Brazilian military view of War.