Causes of hypertension that are amenable to surgical treatment constitute a very small but potentially important segment of the hypertensive population. These causes (which constitute frequently asked questions for medical students) include coarctation of the aorta, aldosterone and corticosteroid-producing tumors of the adrenal glands, lesions producing decreased renal blood flow, and pheochromocytoma. This latter tumor is quite uncommon, with a frequency of roughly one per million, but often produces dramatic hypertensive episodes. Due to its rarity, physicians in practice may not consider the diagnosis and appropriately evaluate the patient. We present the case histories of three patients with pheochromocytoma who demonstrate important features of this disease. Diagnostic evaluation and principles of treatment will be discussed.