We report a rare case of portal-hepatic venous shunt through an enormous portal aneurysm complicated by pulmonary hypertension. A 66-year-old woman was admitted to our hospital for hepatic encephalopathy. Chest roentgenography revealed pulmonary hypertension. Computed tomography and ultrasound examination demonstrated a shunt between the portal and hepatic veins through an enormous portal aneurysm. The diagnoses of portal-hepatic venous shunt and pulmonary hypertension were confirmed by hepatic venous catheterization and cardiac catheterization. Pulmonary hypertension might result from the effects of vasoconstrictive agents, which should be metabolized by the liver in normal subjects, passing through the intrahepatic shunt into the lung.