Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy. The genetic basis of CHI includes a variety of defects in key genes regulating insulin secretion. Mutations in at least seven genes are found in 50% of cases. The most common forms of medically unresponsive CHI, which requires a near-total pancreatectomy are associated with autosomal recessive mutations in the ABCC8 and KCNJ11 genes encoding the two subunits of the pancreatic β-cell ATP-sensitive potassium channel. We report a neonate with CHI and have a novel homozygous splicing mutation in the ABCC8 gene.