The case of an 8-year-old male child with severe kernicterus sequelae is presented in this paper The child hemoglobin value varied between 6.0 and 10.8 g/dL and his reticulocyte count ranged between 3.4 and 46.0% during the steady-state condition and hyperhemolytic crisis, respectively. A chronic hemolytic type of red cell G6PD deficiency was diagnosed. DATA studies indicate that the mutation was G6PD Guadalajara 1159 C --> T (387 Arg -->. Cys) that is situated at the NADP binding site. Additionally, extra nucleotides of (TA) in the A(TA)(n) TAA motif of the promoter region of then ridine diphosphate-glucuronosyltransferase gene (UGT-1 A) were found to be homozygous in the patient. The coexistence of Gilbert syndrome with a chronic type of G6PD deficiency was suggested as a cause of neonatal hyperbilirubinemia leading to kernicterus.