We performed 400 consecutive autopsies in Cairo, Egypt. The intensity of schistosome infection in these cases was measured by counting adult worms recovered by perfusion and dissection and by counting eggs in the tissues of infected cases. Symmers' clay pipestem fibrosis of the liver was clearly related to the presence and intensity of Schistosoma mansoni, but not S. haematobium, infection. Morphologic findings in cases with Symmers' fibrosis were comparable to those in Brazilian cases, and the intensity of S. mansoni infection associated with Symmers' fibrosis was similar in Brazil and Egypt. The fine bilharzial periportal fibrosis described by Hashem was not identified in our material, and Symmers' fibrosis was present in all cases of portal hypertension caused by schistosomiasis. Schistosome eggs were found concentrated in areas of portal fibrosis of cases with Symmers' fibrosis. In the absence of Symmers' fibrosis, eggs did not concentrate in large portal areas regardless of the intensity of infection or the presence of lesser degrees of portal fibrosis. We thus feel it unlikely that Symmers' fibrosis is formed by the fusion of fibrotic granulomas around the schistosome eggs.