Atherosclerosis in 50 nondiabetic patients undergoing hemodialysis was assessed at the time of renal transplantation by intraoperative examination and histologic evaluation of the iliac vasculature. Patients were grouped accordingly: minimal (group 1), moderate (group 2) or severe (group 3) atherosclerosis. Sixty-two per cent of the patients had atherosclerosis, half of them with severe involvement. No sex differences were noted. There was a significant correlation between the patient's age and the degree of atherosclerosis (p less than 0.02). Thirty-five per cent of the patients under 30 years of age had atherosclerosis whereas similarly studied nonuremic control subjects had no atherosclerosis. Metabolic and lipid abnormalities, and duration of hemodialysis did not correlate with degree of atherosclerosis. Hypertension was present in 90 per cent of the patients in groups 2 and 3. When patients between the ages of 25 and 40 years were selected, atherosclerosis was present only in previously hypertensive patients (p less than 0.02). Atherosclerosis may not be accelerated by hemodialysis and may be prevented by more stringent control of hypertension in uremia.