A 66 year-old male patient underwent resection of a pheochromocytoma under general anesthesia. The patient was treated with phenoxybenzamine and propranolol for 7 days preoperatively. Follwing an induction of anesthesia with intravenous fentanly 100 ug, thiopental sodium 250 mg, vecuronium 12 mg, and magnesium sulfate 3.0 gm, endotracheal intubation was performed. Aneathesia was maintained with nitrous oxide, oxygen and isoflurane. For the management of blood pressure during surgical manipulation, magnesium sulfate was infused at the rate of 0.75-1.0 mg/kg/min. After the removal of the tumor mass, the blood pressure dropped to 80/40 mmHg. Whole blood and fresh frozen plasma were transfused and norepinephrine 0.5 ug/kg was infused to maintain the blood pressure for 40 min. Postanesthestic recovery course was uneventful.