The causes of malnutrition in chronic terminal kidney failure are reviewed in the situation both before and after dialysis, as are the malnutrition rates in both circumstances and their treatment. Malnutrition has a high prevalence in terminal kidney patients, partly as a result of the therapeutic restriction on calories and proteins, but also due to the metabolic reactions typical of the disease and to anorexia. In patients subjected to dialytical methods, certain other mechanisms are added. In addition to malnutrition, there are alterations in the metabolism of calcium, phosphorus and potassium, as well as lipids, thus limiting nutritional therapy's ability to restore the nutritional status to normal. An awareness of energy expenditure in chronic terminal kidney failure and the consequences of malnutrition have led to new challenges in nutritional therapy, both in the dose and quality of the proteins, with a debate raging over the advantages of ketoanalogues, and also in the methods for providing nutrients. The ideal nutritional method for repletion is oral administration, but this can be enhanced with artificial support such as oral supplements, parenteral nutrition during dialysis or such alternatives as enteral nutrition at home in the case of chronic kidney problems in children, using percutaneous endoscopic gastrostomy (PEG), in order to nourish the patients and minimize growth disorders.