This chapter discusses the diagnosis, evaluation and management of pheochromocytoma. Pheochromocytoma can present as a hypertensive crisis. This may be triggered by physiological stress including recent surgery, trauma, or pregnancy; tumor manipulation; anesthetic agents at the induction of anesthesia; or drugs including corticosteroids, antiemetics such as metoclopramide, and imipramine. Management of emergencies in patients with pheochromocytoma depends on symptoms. It should always include pharmacological treatment to block the effects of high levels of circulating catecholamines and prevent complications. Hypertensive crisis due to pheochromocytoma should be treated with repeated doses of phentolamine, a continuous infusion of phentolamine, or a continuous infusion of sodium nitroprusside. Definitive treatment for pheochromocytoma is surgery. Emergency surgical removal of the tumor is indicated if the patient deteriorates despite aggressive medical treatment appropriate for pheochromocytoma, even if the patient is critically ill, to increase chances of survival.