A 34-year-old white man with generalized neurofibromatosis was found to have severe renal vascular hypertension due to a coarctation of the abdominal aorta and bilateral renal artery stenosis with saccular aneurysms. Increased renal venous renin activity showed the active involvement of the renin-angiotensin system in maintaining the hypertension. Because the patient refused surgical treatment, antihypertensive treatment with Captopril, a specific inhibitor of the angiotensin converting enzyme was used, resulting in normal blood pressure being restored over an 18 month observation period.