The article analyzes the role of the famous Brazilian diplomat, Minister of Foreign Affairs (1938-1944) O. Aranha in the choice of allies in a difficult international situation, when in Brazil, as in other countries of Latin America, was growing rivalry between the imperialist American power and the rising Germany. Having shown the main activities of O. Aranha in the position of Ambassador of Brazil to the United States, then Chancellor, to revive the “privileged relations” with Washington, the author notes that the strengthening of the alliance with the United States has exceeded the stage of “equidistance” and “pragmatic balance” of president J. Vargas. The turn in foreign policy leads to an aggravation of relations with Germany, the intensification of Brazil's actions to consolidate pan-American unity and the transition of countries from a policy of neutrality to a break in diplomatic relations with the Axis countries. The use of the source base (speeches by O. Aranha, declarations of consultative conferences), and scientific literature made it possible to show how Brazil, in the person of O. Aranha, resisted the spread of Nazism and contributed to the development of Pan-Americanism. © 2023 Ltd "Integration: Education and Science". All rights reserved.