The initial and long-term results of percutaneous transluminal angioplasty of renal artery stenoses are reported. In 4 out of 73 (5.5%) patients the angioplasty catheter could not be placed in the stenotic area. In 67 patients partial or complete dilatation of the segments treated was possible. Complications requiring therapy occurred in 12.3%. Most (80.3%) of the patients were discharged from hospital with completely corrected or improved hypertension. Cure or improvement was noted more often in patients with fibromuscular dysplasia, short history of hypertension, pathologic renin quotient, normal total hippuric acid clearance, or age under 40 years. On follow-up examination a mean of over 14 months after angioplasty 51.7% of the patients had normal blood pressure or less pronounced hypertension, while in 60.9% the total hippuric acid clearance had increased.