Hyperinsulinemia, a common cause of persistent hypoglycemia in infants and children, can result in permanent damage to the central nervous system. Thus, early diagnosis and treatment are important. The typical clinical manifestation of hyperinsulinemic hypoglycemia is symptomatic hypoglycemia that responds poorly to medical therapy. Affected infants may have tremors, jitteriness, apnea, cyanosis, or seizures. If initial medical therapy (frequent feedings, large amounts of intravenously administered glucose, diazoxide, and glucocorticoids) fails to stabilize plasma glucose levels, subtotal pancreatectomy is indicated. This surgical intervention does not completely correct the hypoglycemia in all patients, but it effectively reduces the severity of the condition. Surgical treatment of pediatric patients with Cushing's syndrome or aldosteronoma has also been effective. In our experience, survival of patients with adrenocortical adenomas has been 100%, whereas only five of nine children with adrenocortical carcinomas survived, and four of the five were younger than 10 years of age.