The League of Nations Health Organization (LNHO) played a fundamental role in stabilization policies during the Interwar Period. Public health was considered to be the main factor in this historical context due to the consequences of the war, the postwar crash of the economy and many deep international crises. The LNHO was the cornerstone of international action in many health fields: epidemics, the fight against malnutrition and infectious diseases (malaria, tuberculosis, and yellow fever), infant mortality, drug abuse, the definition of standards (biological, dietary, etc.), the production and compilation of epidemiological records, and public health policies and professionalization. In the process of shaping international health expertise, the collaboration of the LNHO with the International Health Board/Division (IHB/D) of the Rockefeller Foundation (RF) was extremely important, both for the definition of goals and programs, as well as financial support.