We evaluated changes in dialysate losses of protein and absorption of glucose, serum chemistries including protein electrophoresis, and serum lipids among patients who had undergone continuous ambulatory peritoneal dialysis (CAPD) for at least 1 year. The patients' race, sex, and the presence of diabetes mellitus did not influence the results. Over a 2-year period, daily protein losses and glucose absorption from dialysate were constant, serum protein electrophoresis did not show changes consistent with the nephrotic syndrome, serum cholesterol increased after 1 year of therapy but stabilized thereafter, and concentrations of high density lipoproteins did not decrease.