The most common reason for refractory hypoglycemia in newborns is congenital hyperinsulinism. We report a girl with congenital hyperinsulinism due to novel homozygous mutation (c.2041-25 G>A; aberrant splicing mutation) in the ABCC8 gene encoding SUR1 and during somatostatin analog (octreotide) discontinuation developed by nonhypoglycemic seizures. The newborn (birth weight of 3,750 g) was referred to our clinic because of hypoglycemic seizures at 4 h postnatal. On admission, blood glucose was 24 mg/dL and intravenous glucose infusion was started. The patient's insulin level was 27 mIU/mL during the hypoglycemic period. Phenobarbital (5 mg/ kg/day) was added because of short-acting generalized clonic seizures. Although the patient received high doses of diazoxide, esidrex, and octreotide approximately for 2 months, hypoglycemic episodes continued. Then the patient had near-total pancreatectomy, and pathology confirmed a diffuse form of congenital hyperinsulinism. There was homozygous mutation in the ABCC8 gene encoding SUR1, which confirmed the diagnosis of autosomal recessive congenital hyperinsulinism. During octreotide discontinuation, the patient developed non-hypoglycemic seizures, which were controlled by restarting the previous doses. In the light of in vitro and in vivo studies on antiepileptic effects of somatostatin, we believe that seizures in our case have developed secondary octreotide discontinuity.