This article is part of a larger study in which epidemiological and anthropological methods were used to help understand the production and maintenance of schistosomiasis in a small endemic area in Pernambuco State. A cross-sectional study identified several local risk factors for schistosomiasis, quantifying socioeconomic, sanitary, and behavioral variables and then relating them to the prevalence and intensity of schistosomiasis infection. Using univariate analysis, three variables (age group, schooling, and human/water contact) showed significant association with S. mansoni infection. Causal factors and confounding variables were identified through multivariate analysis. Quantitative epidemiological analysis is critically discussed regarding a qualitative ethnographic study in relation to environmental risk situations (contamination and transmission) as well as risk practices (economic and behavioral).