Although pheochromocytoma is an uncommon cause of secondary hypertension, it is also a curable form of hypertension. With proper treatment, the outlook for patients with pheochromocytoma is excellent. If undiagnosed or untreated, pheochromocytoma causes serious complications and death. The key to reaching the diagnosis is a high index of suspicion coupled with careful clinical evaluation and laboratory testing. Our ability to diagnose and localize pheochromocytoma has improved vastly, owing largely to the modern biochemical and radiologic techniques. Despite this, a number of pheochromocytomas remain undiagnosed only to be uncovered after a serious complication or at postmortem. The diverse manifestations and problems presented by patients with pheochromocytoma can be managed only with combined medical and surgical expertise, with assistance from our colleagues from the radiology and anesthesiology disciplines. Although sporadic pheochromocytoma is the most common form of presentation, the overall clinical picture may depend on the subset of affected individual--childhood, pregnancy, associated MEN, and neurocutaneous syndromes. Fortunately, more than 90 per cent of all pheochromocytomas originate in the adrenal gland, but the tumor can occur at any site in the sympathetic chain. The spectrum of clinical manifestations is so wide that a pheochromocytoma may mimic a variety of common disorders. It is as challenging to diagnose what is not a pheochromocytoma as it is to confirm its diagnosis. Surgical removal of pheochromocytoma is the treatment of choice. With proper preoperative medical management aimed at blocking the effects of catecholamines, operative mortality should be close to zero. For patients with inoperable, malignant, recurrent, or multicentric pheochromocytomas, chronic medical therapy is indicated in the form of alpha- and/or beta-blockade or inhibition of catecholamine synthesis with alpha-methyl-para-tyrosine. An understanding of the pathophysiology and natural course is vital to the rational management of patients with pheochromocytoma.