Among 89 allogeneic bone marrow transplant recipients, veno-occlusive disease of the liver (VOD) was diagnosed in 10 patients (11.2%). All cases (n = 5) with schistosomal hepatic periportal fibrosis detected by pretransplant ultrasonography, developed severe fatal VOD in spite of normal initial liver functions and absence of portal hypertension. The incidence of VOD among patients without previous schistosomal contact was 5.95% (5/84). The relative risk to develop VOD was calculated to be 16.8-fold higher in patients with previous schistosomiasis. Schistosomal hepatic periportal fibrosis may thus be added to the known risk factors predisposing to the development of VOD in allogeneic transplant recipients.