Renal artery aneurysms are uncommon, but when they do occur they are frequently associated with hypertension which may be amenable to surgery. Complex arterial abnormalities which formerly would have been treated by nephrectomy may now be reconstructed with preservation of the kidney. This is illustrated by a patient with renovascular hypertension and bilateral renal artery aneurysms, in whom arteriography and renal vein renin ratios were used as a guide to surgery performed in two stages. An in-situ repair was performed on one side. On the other side, where the aneurysm involved the three main branches of the renal artery, an extracorporeal repair was performed using continuous cold perfusion, substitution of the pathological segment with the patient's internal iliac artery, and autotransplantation to the iliac fossa. Both kidneys were retained and the hypertension was cured.