Membranous obstruction of the portal vein has not been previously reported. This 56-yr-old Indonesian man with a history of a tropical fever 5 yr earlier presented with variceal bleeding. Transhepatic obliteration of the varices was attempted, but the catheter placed in the right portal branch would not pass beyond the porta hepatis. Another catheter was inserted into the portal trunk under ultrasound guidance. Simultaneous opacification through the two catheters demonstrated a complete membranous obstruction of the portal vein at the porta hepatis and a portal-superior mesenteric-venous axis that had lost communication with incoming veins and the left portal branch, most likely because of multiple thrombosis. Other angiographic procedures also revealed marked hepatopetal collaterals (cavernous transformation) entering the liver through the hilum. Liver biopsy showed acute post-transfusion hepatitis superimposed upon portal fibrosis. The possible mechanism for membrane formation in relation to thrombosis is discussed.