The most common cause of renal artery stenosis (RAS) is atherosclerosis (90%). Other causes include fibromuscular dysplasia and dissection. Renal artery stenosis is rarely the sole cause of hypertension or renal dysfunction. There is no data that suggest intervention in asymptomatic RAS patients is indicated. The majority of such patients should be managed medically. Symptomatic RAS patients have medically-resistant hypertension (continued hypertension on three medications) or progressive renal failure. Renal ultrasound is the initial imaging for screening. CTA and MRA are more sensitive and specific for determining anatomy and degree of stenosis. Arteriogram should only be performed if intervention is planned. Interventions are now typically via endovascular approach, although knowing indications and techniques for open surgical treatment is also necessary.