We report 2 patients with severe renal failure and hypertension secondary to atherosclerotic renovascular disease who required hemodialysis. Successful surgical revascularization in these patients resulted in the recovery of renal function (twice in a patient) and in controlling the blood pressure. These results indicate that in the presence of severe renal artery obstruction renal parenchyma may be preserved, while renal function is absent. We highlight the usefulness of preoperative renal arteriography for evaluation of the affected vessel and the demonstration of collateral circulation and the value of preoperative renal biopsy in the prediction of the viability of the kidney parenchyma.