Nutritional status and progression of renal failure in 35 children (22 males and 13 females; mean age: 8.85+/-4.13 years) with moderate renal failure were followed for 2 years. All children were on an "ad libidum" diet. Protein intake was determined by a minimum of two dietary diaries kept by the parents and the appearance of urea nitrogen. The children were divided into two groups according to their protein intake: Group 1 - sub-optimal intake (46% of the children, all with significantly lower protein intake); Group 2 - adequate protein intake. The mean protein intake (expressed as a percentage of the WHO recommendations) based on the diets of the patients was 94.79% in Group 1 children and 175.45% in Group 2 children (p<0.05). All patients had a calorie intake of at least 80% of the WHO recommendations. Nutritional status was determined by anthropometric measurements expressed as a standard deviation score. There was no significant anthropometric or biochemical evidence of malnutrition in children with moderate chronic renal failure (CRF). The glomerular filtration rate (GFR) in patients with a sub-optimal intake of protein was -5.41+/-2.87 ml/2 year versus-9.53+/-8.61 ml/2 year in the normal protein intake group. There was no correlation between protein intake, nutritional status and progression of renal failure in children with moderate CRF within the 2-year study period.