A 69 year-old male patient was admitted for lumboperitoneal shunt operation due to normotensive hydrocephalus. There was not significant laboratory findings except slightly increased serum potassium(5.0 mEq/1). But we ignored this hyperkalemia probably due to hemolysis because ECG at word and operation room did not reveal any evidence of hyperkalemia. Following induction of an anesthesia with fentanyl 100 ug thiopental(2.5%) 100 mg injection, succinylcholine 60 mg was administered intravenously, and endotracheal intubation was performed. Vecuronium 5 mg was administered intravenously for neuromscular blook. Anesthesia was maintained with nitrous oxide, oxygen and enflurane. During the course of operative procedure, his vital signs were stable(blood pressure 120/70 mmHg, pulse 60/min). After lumboperitoneal shunt was completed without problem, neostigmine 5 mg and glycopyrrolate 0.2 mg was administered for reversal of vecuronium. About 10 minutes after arrival in recovery room, his general condition deteriorated suddenly and radial arterial pulse could not be palpated. Radial arteiial blood pressure wave did not appear and ECG showed asystole and stand-still. Cardiopulmonary resuscitation(CPR) was started with Ambu-bagging, sodium bicarbonate and epinephrine injection with external cardiac massage, but the immediate response was not so good. We re-examined the patients chart and found the past history of chronic renal function impairment. CPR was directed for hyperkalemia including calcium chloride, sodium bicar-bonate and 10% dextrose with insulin. At 5 minutes after CPR, ECG showed regular sinus rhythm with stable vital signs. But ECG still showed hyperkalemic pattern(high tented T wave and prolonged P-R interval). After vigorous and continous treatment for hyperkalemia in recovery room, he regained consciousness and he was transfered to the neurosurgical intensive care unit for further evaluation and treatment. Postoperative course was relatively good and he was discharged on 25th postoperative day without any sequale of cardiac arrest.