The aim of this Topic is to discuss nutritional support in critically ill patients. Methods to assess the nutritional status of ICU patients as well as the indications to nutritional support will be presented. Actions to maintain homeostasis during nutrition care, to evaluate the energy and protein needs and to promote adequate nutrition on a daily basis will be introduced. The use of early enteral feeding, early supplemental parenteral nutrition will be discussed. Indications to immunonutrition will be given and controversies will be reviewed. Prevention and management of the common complications of nutrition support will also be presented.