Of 26 patients with pheochromocytoma treated between 1974 and 1986, two presented with pheochromocytoma crisis. This unusual presentation consists of hyper- and/or hypotension, high fevers (greater than 40 degrees C), encephalopathy, and multiple organ system failure. Both patients had large tumors associated with markedly elevated levels of epinephrine. Although hypertension was adequately controlled in both patients with phenoxybenzamine, phentolamine (1 patient) and nitroprusside, both patients deteriorated rapidly. The first patient expired during attempts to identify a source of sepsis. None was found at autopsy. The second patient underwent urgent adrenalectomy which reversed the multiple organ system failure and resulted in patient survival. We conclude from review of these patients and three others in the literature that (a) crisis is an unusual presentation of pheochromocytoma; (b) its manifestations include vascular lability, high fever, encephalopathy and multiple organ system failure; (c) it may be the result of increased epinephrine secretion; (d) successful treatment of pheochromocytoma crisis demands prompt diagnosis, vigorous medical therapy and emergent tumor removal if the patient continues to deteriorate.