Pheochromocytoma crisis is a rare life-threatening event that may appear with a variety of clinical symptoms. We present three cases of life-threatening crisis in which magnesium sulfate was particularly beneficial in controlling symptoms and signs when more conventional forms of therapy had failed. Two patients presented with hypertensive encephalopathy, and the third presented with catecholamine-induced cardiomyopathy. All three patients successfully underwent tumor excision with magnesium sulfate used as the sole drug for control of hemodynamic disturbances during surgery. The problems of pheochromocytoma crisis and the potential benefits of magnesium sulfate in this condition are reviewed.