The influence of nutritional status and hormonal growth activity on the impaired somatic development of adolescents with the hepatosplenic clinical form of Schistosoma mansoni infection (HS), the intestinal form with high (IH) or low (IL) egg output and non-infected (NI) individuals was evaluated (in Comercinho, Minas Gerais State, Brazil, in 1996-97) by measuring body mass index (BMI), insulin-like growth promoting factor (IGF-I) and its carrier protein (IGFBP-3). BMI, IGF-I and IGFBP-3 concentrations were significantly lower in the HS group compared with the IH and the NI groups, irrespective of age. BMI did not remain associated with the clinical form in the bi-variate model that included IGF-I and BMI or IGFBP-3 and BMI, suggesting that in these groups IGF-I and IGFBP-3 levels were related to the clinical form but independent of nutritional status. It is suggested that physical growth impairment in hepatosplenic S. mansoni infection results from the synergistic action of both hepatic damage and nutritional restriction.