A 72-year-old woman consulted our hospital for a cystic mass in the right kidney. Ultrasonography and drip infusion pyelography revealed a right renal cystic mass 10 cm in diameter and right hydronephrosis. Computed tomography (CT) and magnetic resonance imaging revealed a giant mass with partial calcification in the right renal hilus. The mass was diagnosed the fusiform aneurysm 10 cm in diameter occurring in the main stem of right renal artery by selective abdominal angiography and 3-dimensional CT. We performed total nephrectomy and the histological finding was atherosclerosis. A total of 485 cases of renal artery aneurysm have been reported in Japan. These cases and 15 cases of renal artery aneurysm more than 5.0 cm in diameter are herein reviewed.