During an 11-yr period (1979-1989), we have experienced five patients with idiopathic Budd-Chiari syndrome (BCS), four (80%) of whom had associated hepatocellular carcinoma (HCC). In contrast, the incidence of BCS complicated by HCC was 0.7% of a total of 556 patients who underwent surgery for HCC or were autopsied. Hepatitis B virus-related antigen or antibody was positive in one patient each. Four of our five patients were asymptomatic and were initially diagnosed by ultrasonography (n = 3) or computed tomography (n = 1). The hepatic parenchyma histopathological findings were cirrhosis and fibrosis in one each. Infection of hepatitis B virus rather than BCS was speculated as a causative factor for HCC in two patients. Membranous obstruction with spotty calcification, intrahepatic bizarre communicating vessels, and the dilated anterior longitudinal veins in spinal canal were recognized in three patients. Three patients had two HCCs which were similar in size and arose from the right and left hepatic lobe, separately, suggesting multicentricity of HCC. Both percutaneous transluminal angioplasty with Gruntzig balloon catheters for the obstruction of the inferior vena cava and hepatic arterial embolization for HCC(s) were performed in three patients. These patients survived 29.3 months on average after the diagnosis of BCS complicated by HCC(s). The opened IVC was confirmed to be patent on an average of 26.3 months after the first angioplasty.