context: blood transfusion is one of the major risk factors for the transmission of the hepatitis b (hbv) and c (hcv) viruses. however, there are no reports describing the endoscopic transmission of these viruses in patients with the hepatosplenic form of schistosomiasis. objective: to estimate the prevalence of serological markers of hbv and hcv in patients with the hepatosplenic form of schistosomiasis and evaluate the possible risk factors associated with these infections. methods: a cross-sectional study was conducted on 230 patients with hepatosplenic form of schistosomiasis who attended a university hospital in recife, northeastern brazil, from february to august 2008. the patients answered a standardized questionnaire about risk factors. serum samples were analyzed for anti-hbc total, anti-hbs, hbsag, and anti-hcv using enzyme-linked immunosorbent assays. univariate analysis and multiple logistic regression were performed. results: the prevalence was 30% for anti-hbc total and/or hbsag and 7.4% for anti-hcv. there was a higher frequency of the serological markers in females and in patients aged .50 years. a significant association was detected between the presence of anti-hcv and the receipt of six or more blood transfusions. there was no association of history and number of digestive endoscopies with the serological markers analyzed. conclusions: we observed a higher prevalence of serological markers for hbv and a lower prevalence of anti-hcv. our results indicate that females and patients of an advanced age are the most affected categories and that patients that received multiple transfusions are at a higher probability of hcv infection.