Nutritional support for children with cancer is predicated on the belief that optimal nutrition promotes tolerance of anti-neoplastic therapy and preserves immunologic responsiveness. The use of nutritional support is based on the assumption that there is effective therapy for the primary disease and that there will be a predictable period of nutritional stress. The most common nutritional problem is posed by the failure of sick children willingly to eat enough to maintain nutritional homeostasis. Supplementation of oral intake with a nutritional formula given by a small-bore nasogastric tube is simple, effective, and economical. If the sum of oral and tolerated nasogastric tube feedings is less than that required for optimal nutrition, unmet needs may be satisfied by nutrients given into a peripheral vein. Total parenteral nutrition, given by central vein, is reserved for situations in which the combination of enteral and peripheral venous alimentation is inadequate.