Cross-section studies on prevalence and morbidity of schistosomiasis mansoni are presented for the county of São Lourenço da Mata, state of Pernambuco, as part of a long term project which is being carried out in Northeastern Brazil. The survey was made in the City of São Lourenço da Mata and in 8 rural localities. Prevalence of Schistosomiasis and other helminth infections were very high. Hepato-splenic for ms varied from 1 to 2 per cent.