The Mambaí Project was launched in 1980 for the purpose of making a longitudinal clinical-epidemiologic study of Chagas' disease and of serving as a pilot program for the Ministry of Health of Brazil. At the beginning of the project, a census was carried out, the housing units were evaluated, and clinical examination and laboratory tests were performed on the population. After a phase of massive attack with insecticides, ongoing epidemiologic surveillance was instituted in order to detect residual foci of triatomine bugs in all the housing units in the municipality. The campaign included a program of health education combined with community participation. All infested housing units were selectively fumigated. In 1988 a new census was carried out, together with a serologic survey of children born after the control program was initiated. This article describes the results of epidemiologic surveillance during the first 13 years of the program. The prevalence of T. infestans in the housing units diminished to levels that suggest that vector transmission of the disease in Mambaí has been stopped. However, the risk of reinfestation from neighboring areas without control programs and the risk of colonization by secondary T. sordida vectors are factors that should be carefully monitored.