In 2004, the Federal Government introduced the "Farmácia Popular do Brasil" Program, which was an example of policy innovation, establishing a co-payment scheme as a strategy for access to medication. The study analyzed the original model of the Program. Data were obtained from interviews with key stakeholders, program documents and user prescriptions and registers. The results showed widespread expansion of the PFPB network and in the number of people attended. Despite the ever-increasing number of people attended with prescriptions from the private sector, a large demand from public sector users, namely the original focus of the program, was observed. From the standpoint of the federative pact, the program reinstates the centralized model of essential medication distribution which, in the decentralized public system is under state and municipal responsibility. The results point to the difficulty in compliance by states and municipalities with medication distribution responsibilities, mainly in the North and Northeast regions of Brazil. The study concludes that the population has been consistently turning to the PFPB for essential medication it has not been able to access in the public sector.