Nesidioblastosis is a rare disease characterized clinically by persistent hypoglycemia with inappropriately elevated circulating insulin concentration. Adequate early diagnosis should be established and subtotal pancreatectomy performed before itreversible cerebral damage caused by glucose deficit. The authors got a chance to anesthetize 56-day-old male patient for subtotal pancreatectomy because of nesidioblastosis, Following an induction of anesthesia with intravenous thiapental sodium 5 mg/kg and succinylchohne 1 mg/kg, endotracheal intubation was performed and anesthesia was maintained with pancuronium bromide and O2-N2O-enflurane. Intravenous fluid was maintained with 1-2-3 solution 30 ml and 15% D/W 40 ml mixed with 20 ml of 20 mEq/L NaCI.