a prospective study was undertaken in 1,520 children less than 15 years of age in s？o josé de ribamar, maranh？o, brazil, from june 1994 to january 1995, to evaluate the prevalence and characteristics (socioeconomic, environmental, and behavioral) associated with infection by leishmania chagasi. montenegro skin test (mst) and enzyme-linked immunosorbent assay (elisa-rk39 and crude) test were used to detect infection. the statistical analysis used the c2 test with yates correction and a p value less than 0.05 was considered statistically significant. prevalence of infection was 61.7% as measured by mst, 19.4% according to elisa (rk39), and 19.7% by elisa (crude). association was detected between leishmaniasis in the family, water supply, application of insecticide, and infection by l. chagasi using mst. no association with infection by l. chagasi was detected using elisa rk39 or crude. more effective control measures are needed to reduce prevalence and to detect asymptomatic cases in this high percentage of infected children.