The clinical features of 6 cases with severe veno-occlusive disease (SVOD) in 43 patients who received hemopoetic stem cell transplantation (HSCT) in our institute from May 1983 to March 1994 were reported. The incidence of SVOD was 14% of the 43 patients, and 7.9% of those received autologous bone marrow transplantation (ABMT), SVOD occurred within 3 weeks after HSCT in all the 6 cases and was manifested by painful hepatomegaly, jaundice, hyperbilirubinemia, increase of serum liver enzyme level and ascites. Although supportive and symptomatic treatment including steroids were given, all patients died of progressive multiorgan failure within 4 weeks after HSCT. It is suggested that SVOD of the liver is a major and often lethal complication of HSCT and prophylaxis of this disorder with anticoagulant and antiplatelet agents is essential in clinical HSCT.