21 patients (male: 10) with average ages of 53.5 suffering chronic renal disease due to different causes received the reduced protein diet and supplementation of Ketoacids (Ketosteril). The average monitoring duration was 16.6 months.The results have shown that blood creatinine was reduced in 10 patients, was not changed in 6 patients and was increased in 5 patients after 1 months of treatment. The study concluded that the reduced protein diet combined with supplementation of ketoacids played an important role to slow the progression of renal failure and prevent patients from malnutrition.