Renal artery stenosis is an important clinical entity. its importance lies in that it may be a treatable cause of hypertension, and it is -when progress- a cause of chronic renal failure. The causes of renal artery stenosis are numerous, the most common are: atherosclerosis and fibromuscular dysplasia (accounts for more than 95% of cases). Digital Subtraction Angiography (DSA) is the standard reference in the radiologic diagnosis of renal artery stenosis, but it carries the risk of being invasive procedure. Doppler ultrasound is used in the evaluation of the renal arteries, and it has the advantage of being non-invasive and inexpensive.