Brazil has a long tradition in the public health arena, with roots that can be traced to the colonial period, when the first medical schools were established in the country. The recent history of the field, however, became deeply intertwined with the struggle to re-democratize the country after the military coup of 1964. As part of a broad coalition, the movement for health reform was seeded by left-leaning public health physicians who were instrumental in designing what would become Brazil’s national healthcare system, the Sistema Único de Saúde (SUS), after the restoration of democracy. The creation of the Instituto de Medicina Social (Social Medicine Institute, IMS) at the Universidade do Estado do Rio de Janeiro (Rio de Janeiro State University) in 1970 was closely followed by the introduction of its Masters course in Social and Preventive Medicine in 1974, one of the pioneers in the field in Latin America, and is an important part of this development. The professors and researchers at the IMS were important actors both in the development of a theoretical body of work as well as in political at different levels of government. The account of this institution’s history, partially based on personal experience, is an important element of the general history of the field in Brazil.