[The origins of the basic healthcare system in Brazil: the District System of Sanitation Administration].

There exists an interaction between multiple issues involving policy making, the building of knowledge and the implementation of practices in the health sector, which results in the particular way health services are provided in different historical contexts. The emergence and consolidation of sanitation organization was the result of a political process based on an idea of meeting the needs perceived in a given historical context. The historical course taken by the basic healthcare system in Brazil is analyzed from the perspective of its organizational and welfare principles, its expansion in physical terms, and its function within the public health system between 1918 and 1942. The article seeks to describe in detail the antecedents and initiatives taken in the establishment of a district system of sanitation administration, first in Rio de Janeiro and later across Brazil, which was a precursor of the basic healthcare system in Brazil.