The increasingly frequent use of arteriography in the investigation of hypertension and of obliterative arterial disease of the lower limbs has led to recognition of the actual incidence of renal artery aneurysms. The importance of this type of lesion is due to the fact that the natural history of renal artery aneurysms remains unknown, their relationship with hypertension is still controversial and the risk of complications, and rupture in particular, has led to the suggested possible need for their routine surgical excision. The current trend is to limit indications for surgery to certain specific cases since a number of recent series have shown that the risk of rupture of a small saccular aneurysm was very small.