Intravenous digital subtraction angiography was performed in 80 patients operated on for renovascular hypertension. Preoperative angiography (33 patients) was used for evaluation of the hypertensive state and provided accurate visualization of the renal arteries in two-thirds of the cases; confirmatory arteriography was necessary in one-third of the patients. Postoperative angiography was performed in 67 patients (20 of whom also had preoperative angiography) and provided excellent visualization of the reconstructed renal artery in all cases. Intravenous digital subtraction angiography is particularly useful in renal transplant patients, since stenosis of the renal artery is frequent in transplanted kidneys.