We designed a short-term randomized controlled study in 12 adult patients with chronic renal failure to assess the metabolic effects of a low-protein diet (LPD) supplemented or not with ketoacids (Cetolog, Clintec Corp., France). Dietary survey included a monthly 3-day food record and a 24-hour urinary urea measurement. After a baseline period (1.11 g protein, 31.7 kcal/kg BW/day), patients reduced their protein intake (PI) to 0.71 g/kg BW/day. Energy intake (EI) was kept constant (31.4 kcal/kg BW/day) during the 3-month period. Baseline plasma lipids did not show overt hyperlipemia. After reducing PI, a significant increase in apolipoprotein AI and the Apo-AI/Apo-B ratio was observed. Plasma Lp(a) levels were elevated at baseline and did not change during the 3-month LPD period. There was no difference between groups receiving ketoacids or not. Thus, in adult chronic renal failure, under a sufficient EI, reducing PI by 40% had a beneficial effect on plasma lipid profile. This improvement in lipid profile might reduce the high cardiovascular risk in these patients.