The development of gastric acid-protected pancreatic extracts has radically transformed the diet of patients with cystic fibrosis, who are now provided with a high-caloric, hyperproteinic and normo- or hyperlipidic diet, with a correct supplementation in minerals, vitamins and oligo-elements. Nutrition has a major influence on the course of the disease, and the evaluation of the patients' needs has already shown that these are clearly increased in cystic fibrosis. In the severe and advanced forms of the disease, when refractory anorexia is added to chronic infection, more or less sophisticated techniques of nutritional assistance, such as oral supplementations and enteral or even parenteral feeding, are carried out. These techniques not only improve the anthropometric nutritional parameters, but if they have been prescribed soon enough they also interfere with the outcome of the disease.