Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an inherited deficiency of an enzyme necessary to protect the erythrocyte from oxidative stress and hemolysis. Without this enzyme, affected neonates are at risk for acute onset of hemolytic jaundice and severe sequelae, from hearing loss and mild retardation to kernicterus. In some populations, especially in blacks and those of Mediterranean ancestry, the incidence of G6PD deficiency has been reported to be as high as 10% to 14%. We describe a female newborn who had acute onset of hyperbilirubinemia leading to kernicterus in the first week of life. Investigation proved G6PD deficiency. This case suggests a need to screen for this disease or to follow serial bilirubin levels in populations at risk.