Twenty two patients having indication for surgical treatment of portal hypertension due to hepatoesplenic schistosomiasis were prospectively studied. Each patient was submitted to preoperative monitoring with pulmonary artery catheterization. The results showed hemodynamic alterations characterized by an increase of cardiac index (4.50 +/- 0.96 l/min/m2) associated to a decrease of systemic vascular resistance index (1638.60 +/- 441.86 dyn.s/cm5.m2). The stroke index and all right and left cardiac work indeces were increased. The pulmonary artery mean pressure was increased (17.23 +/- 8.63 mmHg) and the pulmonary vascular resistance index was decreased (147.95 +/- 126.21 dinas.seg/cm5.m2). We concluded that hepatoesplenic schistosomiasis determines hyperdynamic systemic circulation, probably correlated with portosystemic shunt, and pulmonary hypertension.