Renovascular hypertension is the most common cause of secondary hypertension. Interest in identifying patients with renal artery stenosis has been stimulated recently by advances in three areas. First, is the realization that not only can renal artery stenosis cause renovascular hypertension, but it can also lead to progressive renal failure (ischemic nephropathy) caused by progression of disease, usually atherosclerotic in nature. Second, advances in percutaneous transluminal renal angioplasty and, especially, the recent use of renal stents has led to a less invasive management of these patients as compared with traditional renal revascularization. Finally, the development of newer less invasive diagnostic techniques, both for the identification of patients with renal artery stenosis and to follow patients with known renal artery stenosis, has simplified the diagnostic aspect of the disease.