Nutritional support is an integral and essential part of the management of 5-10 percent of hospitalized children. Children in the intensive care unit are particularly likely to develop malnutrition because of the nature and duration of their illness, and their inability to eat by mouth. This article reviews the physiology of starvation and the development of malnutrition in children. A method of estimating the nutritional requirements of children is presented. The techniques of nutritional support, including enteral, peripheral, and central parenteral nutrition are discussed in detail. Appropriate formulas are given for different age groups. Electrolyte, vitamin, and mineral supplements are discussed. Guidelines are provided for choosing between peripheral and central total parenteral nutrition. A monitoring protocol is suggested and complications of nutritional therapy are reviewed. Safe and effective nutritional support requires considerable investment of time and effort by members of the nutrition team.