In a series of 50 patients (22 females, 28 males); 52 ostial renal artery stenoses were treated by transluminal balloon angioplasty. The mean age of patients was 66 years (range 36-81); mean arterial pressures were 181 mmHg for the systolic pressure and 87 mmHg for the diastolic pressure. The mean level of serum creatinine was 179 mumol/l +/- 128. An immediate success was obtained in 86.5% (residual stenosis of 26%). There were 7.6% of immediate failures and 13.5% of residual stenosis above 50%. Mortality within 1 month was observed in 2 patients. Morbidity included one aortic dissection and 5 cholesterol embolisms. After a mean follow-up of 10 months, 78% of the series were controlled: 66.6% exhibited a residual stenosis below 50%, 25.9% had restenosis and 7.4% had an occlusion of the renal artery. Since patients with ostial renal artery stenosis constitute a high surgical risk group, transluminal balloon angioplasty might be considered as an acceptable and safe alternative treatment.