We prospectively studied 21 consecutive patients with extrahepatic portal venous obstruction for evidence of biliary tract disease. Two patients were first seen with extrahepatic cholestasis; another had recurrent cholangitis. All three patients with clinically manifest biliary disease were adults. Another five patients had icterus on clinical examination. Liver function tests revealed elevated bilirubin levels in 14 patients (66.6%), elevated alkaline phosphatase levels in 17 (80.9%) and elevated serum ALT levels in 8 (38.0%). Endoscopic retrograde cholangiography revealed abnormal findings in 17 patients (80.9%). The changes involved the common bile duct (66.6%) more often than they did the hepatic bile ducts (38.1%). Cholangiographic abnormalities included strictures (52.4%), caliber irregularity (23.8%), segmental upstream dilatation (42.8%), ectasia (9.5%), collateral veins causing extraluminal bile duct impressions (14.3%), displacement of ducts (9.5%), angulation of ducts (4.7%) and pruning of intrahepatic ducts (9.5%). The pathogenesis of such cholangiographic abnormalities is unknown. However, possible factors in such changes include collateral veins bridging the blocked portal vein, causing bile duct impressions; fibrous scarring of porta hepatis, causing angulation of bile duct; and ischemic injury to bile duct, leading to stricture formation and caliber irregularity. Biliary disease is important in the clinical outcome of patients with extrahepatic portal venous obstruction because variceal sclerotherapy has prolonged the life expectancies of such patients. (HEPATOLOGY 1993;17:807–813.)