Peritoneal dialysis is associated with nutritional abnormalities due to peritoneal glucose absorption and protein or amino acid losses into the dialysate. Nutritional assessment, every four months, is essential, based on body composition, anthropometric measurements, clinical characteristics, biochemical parameters and dietary survey. Thus 1.2 g to 1.3 protein/kg/day and 30 to 35 kcal/kg/day energy intake may be required. Oral, parenteral or intraperitoneal amino acids supplementation can improve the nutritional status in peritoneal dialysis patients.