The actual knowledge about leprosy and its therapy determines it to be regarded and treated as any other disease. Leprosaria, dedicated to segregation and isolation the patient are not needed anymore. Accordingly, the only leprosarium that existed in Costa Rica, the "Sanatorio Nacional de las Mercedes", was closed on March 30, 1979. We are providing a historical account of the stages in the struggle against leprosy leading to the closure of the Sanatorio, as well as the main reasons supporting the inadequacy of having such an institution. We explain the meaning and advantages of the foster homes, where the last 30 remaining patients were replaced, thus facilitating the closure of the Sanatorio. Finally, three years later, we discuss the most significant results concerning the Hansen's disease control in Costa Rica.