Renal arterial disease occurs in 3-5% of patients with systemic hypertension. It is important to determine the type of lesion by arteriography to understand the natural history of the specific disease and to choose appropriate therapy. Some have questioned why arteriography should be performed if an operation or percutaneous transluminal renal angioplasty is not considered. One must keep in mind that if the arteriographic characteristics are known, the specific lesion and its course may be predicted, resulting in better management of the disease. In patients with a unilateral lesion angiotensin converting enzyme inhibitors are efficacious, but calcium antagonists may also be used. However, if therapy does not provide optimum control of blood pressure or the impairment of renal function progresses, then percutaneous transluminal renal angioplasty or surgery should be reconsidered.