The goal of pediatricians involved in the nutritional management of preterm infants is to mimic intrauterine growth and to obtain a functional outcome comparable to that for infants born at term. Appropriate administration of nutrients in the first few days to weeks of life will reduce the growth restriction that is frequently observed. Existing guidelines advise providing preterm infants with both amino acids and lipids from birth onward. Despite this knowledge, many hospital units do not comply with these guidelines. Further improvement of the quality of the composition of parenteral solutions for both neonates as well as older children should be the subject of further research.