We have reviewed the records of 18 patients with intrahepatic, and 15 with extrahepatic portal vein obstructions. There were a variety of causes, but we think it is significant that only three of these patients had a history of an exchange transfusion at birth. An equal number had associated congenital vascular defects. Seven splenoportograms done in children with extrahepatic obstructions showed an early stage of development of the portal vein. Variceal hemorrhage was the most serious complication of portal hypertension, regardless of its cause. Hypersplenism was more common in children with liver disease, but in itself did not cause the child any difficulty. Only five children of 17 who had splenorenal shunts did not have postoperative bleeding.