The clinical diagnosis of orthostatic hypotension (OH) is straightforward and usually does not require extensive laboratory testing. Symptoms of cerebral hypoxia may not occur even with low BP because of compensatory cerebral vascular autoregulation. Autonomic function tests may pinpoint the lesion in OH, but they should be selected carefully. Heart rate response to standing, the valsalva maneuver, the cold pressor test, and plasma norepinephrine levels are the most useful. General measures in management, eg, nocturnal head up tilt and use of a pressure-support garment, often will provide major relief of symptoms. The mainstay of drug therapy is fludrocortisone acetate, but edema, supine hypertension, and heart failure occur frequently. Other agents (eg, vasopressors, prostaglandin inhibitors, and beta-adrenergic blockers) may enhance effectiveness of therapy when combined with fludrocortisone acetate.