We set out to assess the long-term benefits of renal percutaneous transluminal angioplasty (PTA) in 107 consecutive hypertensive patients with atheromatous renal artery stenosis. During 12-month follow-up, blood pressure fell to normal levels in 10 (8.8%) patients and improved in 76 (67.3%); renal function improved or remained stable in 74% of patients. In patients with atheromatous disease, renal angioplasty was most successful in those with stenosis in a single functioning kidney, and in nine patients who presented with symptoms and signs of heart failure, in the absence of overt ischaemic or valvular heart disease. In the latter group, renal PTA resulted in a large loss of sodium and water, resolution of the 'apparent' heart failure, and a marked improvement in blood pressure and renal function. It is suggested that all hypertensive patients with haemodynamically significant renal artery stenosis (and/or mild to moderate impairment in renal function), should be considered for renal PTA. Patients with atheromatous stenosis in a single functioning kidney, and those who present with signs of sodium and water retention, are likely to benefit most.