The aim of the present communication is to address the exchanges of scientists and students between Brazil and Nazi Germany from 1933 to 1942, when Brazil entered World War II on Allied side. The scientific relations between Brazil and Germany in those years were associated, on the one hand, by the interests and strategies of the cultural diplomacy from Berlin. On the other hand, the individuals involved in this exchange tried to make possible the efforts to intellectual cooperation and institutional projects. One field of these relations was the appointment of German professors to the Brazilian universities, in the moment when these were emerging as the principal centres of training and scientific research. In such case, the tensions brought by the Nazi policy of exclusion of Jews academics reflected in the microcosms of the Brazilian scientific community. The scientific expeditions directed to Brazil constituted a much dynamic aspect of the Brazilian-German exchanges. Their objectives were to make researches in fields such as genetic and racial hygiene, natural history, geography and ethnography. Here is to mention the expeditions of Ernst Nauck and Gustav Giemsa (1936), Hans Krieg (1937-1938), Otto Schulz-Kampfhenkel (1935-1938) and Adolf Schneider with Helmut Sick (1939-1942). This paper intends to explore the goals, interests and tensions that followed these undertakings, the scientists and institutions who supported them in both sides of Atlantic, as well as the impacts they had in scientific agendas, mutual knowledge, and in the political bilateral relationships, marked by intense commercial exchanges and affinities between authoritarian regimes in the two countries.