The author presents a perfusion teehnique to recover S. mansoni worms from corpses. Cases of fibrosis of Symmers showed greater number of worms than asymptomatic ones. Howewer, hospital post-mortem examinations were difficult to evaluate as cases of Symmers fribrosis came chieíly from the hinterland and asymptomatic cases proceeded from city. The worm burden in cases withouth Symmers fibrosis was variable but always related to the in- tensity of infection.