Although a rare cause of secondary hypertension, timely recognition and management of pheochromocytoma are crucial to prevent serious complications that can result from this tumor. The cause of pheochromocytoma is unknown. It may be a component of a polyglandular endocrine disturbance or associated with other neuroectodermal tumors, but usually it is recognized as an isolated finding. Because of the variable clinical manifestations, proper diagnostic quest for pheochromocytoma depends on a high index of suspicion. Availability of biochemical assays for catecholamines and their metabolites has improved our ability to establish or exclude the diagnosis of pheochromocytoma in a suspected patient. However, before ordering the biochemical tests, it is important to be certain that the patient has not taken any drugs or substances that can lead to a spurious value. Confirmatory localization of pheochromocytoma has become a straightforward exercise owing to current radiological techniques. Blockade of the effects of catecholamines provides the pharmacological basis for medical treatment of pheochromocytoma. Surgical removal of the tumor is the treatment of choice for most patients with pheochromocytoma.