The authors carried out a retrospective survey assessing the total proportion of diabetic patients and relative proportion of patients with Type I and Type II diabetes among patients receiving renal replacement therapy and those evaluated for chronic renal failure in a southern Italian renal unit during the period 1972-1986. The proportion of diabetics among patients accepted for renal replacement therapy was 10% (34/336); of the 34 diabetic patients, only one was clearly affected by Type I diabetes, 26 had Type II diabetes, and the classification was uncertain in four patients. Similar relative proportions of Types I and II diabetes were observed among patients referred during the same period for evaluation of chronic renal failure.