Type 2 Crigler-Najjar syndrome is a rare hereditary disorder characterized by chronic, nonhe- molytic and modest unconjugated hyperbilirubinemia. There are currently reported three types ot' syndrome: Gilbert, Type 1 and 2 Crigler-Najjar syndrome. Type 2 Crigler-Najjar syndrome is cau- sed by hereditary glucuronosyl transferase deficiency and it can be differentiated from the Gilbert and Type 1 Crigler-Najjar syndrome by the severity of hyperbilirubinemia and its response to phenobarbital administration. We expierienced a 22 year-old male patient who had shown persistent jaundice and unconjugated hyperbilirubinemia from adolescence. It was noted that several persons had shown jaundice among his maternal family. The plasma bilirubin concentration was elevated after fasting for 48 hours and was decreased dramatically by phenobarbital treatment. (Korean J Gastroenterol 1995;27:4S8 - 492)