From June 1981 to June 1985, 22 patients with advanced chronic renal failure were treated with a preparation of ketoanalogues of essential amino acids (Ketosteril, 1 tablet/5 kg/day) combined with a protein supply of 0.4 g/kg/day. At the beginning of treatment, their mean plasma creatinine was 762 +/- 135 mumol/l and their creatinine clearance, 8.4 +/- 3.1 ml/min/1.73 m2. By the end of November, 1985, among the 20 assessable patients, 4 had been on ketoanalogues for 8 to 52 months, 9 had to be dialyzed after 4 to 20 months, 5 had died and 2 had abandoned treatment. A mean 28% decrease in plasma urea level and daily urinary urea output was observed after 1 month on ketoanalogues, and a sustained reduction in plasma creatinine was observed in 12 patients. Mean renal survival was 15.6 +/- 12 months (median: 12 months), and was longer in patients whose plasma creatinine was lower than 700 mumol/l at the beginning of treatment. The ketoanalogues were well tolerated, and no denutrition occurred. Our experience confirms the usefulness of this therapeutic approach in uremic patients and suggests that the best results would be obtained if ketoanalogues were introduced before end-stage renal failure.