We present a case of severe persisting unconjugated hyperbilirubinemia in a Uigur infant boy,eventually diagnosed as Crigler-Najjar syndrome type I.DNA analysis of his blood of the UGT1A1 gene sequence demonstrated that he was homozygous for an insertion mutation causing a change of the coding exons with a frame-shift,resulting in the substitution of 27 abnormal amino acid residues in his hepatic bilirubin uridine diphosphoglucuronyl transferase enzyme.Both of his parents were heterozygous for the same mutation.A novel frame-shifting mutation of the UGT1A1 gene was found,confirming the diagnosis of Crigler-Najjar syndrome type Ⅰ for this patient.