This study evaluated the long-term effects of percutaneous transluminal renal angioplasty (PTRA) on blood pressure and renal function in patients with renovascular hypertension. Seventy-eight patients with hypertension and unilateral or bilateral stenoses of the renal arteries (16 with fibromuscular dysplasia and 62 with atherosclerosis) were studied. All patients with fibromuscular dysplasia (group A) had normal renal function, while 27 of the 62 patients with atherosclerosis (group B) presented with various degrees of renal failure. PTRA was technically successful in 87.5% patients of group A. The overall technical success rate (complete plus partial) was 72.3% (55/76 renal arteries) in group B. Mean follow-up (range) in months was 42 (12-108) for group A and 39 (13-106) for group B. After successful PTRA, the overall benefit rate (cure plus improved) for hypertension was 100% in group A; 10 of 14 patients were cured and 4 of 14 were improved. In group B, the overall benefit rate was 70.8%; 9 of 48 were cured and 25 of 48 were improved. PTRA was technically successful in 18 of 27 patients with renal failure. Renal function improved in 4 of 18 patients, remained stable in 9 of 18, and deteriorated in 5 of 18 patients. The above results suggest that PTRA is an effective method for the long-term management of patients with renovascular hypertension, although the results were less favorable in the presence of bilateral renal artery stenoses: in addition to improved control of blood pressure, PTRA might improve renal function or delay its progressive deterioration.