Preterm infants have limited nutrient stores at birth, take time to establish enteral feeding, are at risk of accumulating significant nutrient deficits, and frequently suffer poor growth-all risks which are associated with poorer neurodevelopmental outcome. Parenteral nutrition (PN) provides a relatively safe means of meeting nutrient intakes, and is widely used in preterm infants in the initial period after birth. PN is also important for infants who may not tolerate enteral feeds such as those with congenital or acquired gut disorders such as necrotizing enterocolitis (NEC). PN is associated with several short-term benefits, but clear evidence of long-term benefit from controlled trials in neonates is lacking. There are many compositional, practical and risk aspects involved in neonatal PN. In most preterm infants, authorities recommend amino acid intakes approximating to 3.5-4 g/kg/day of protein, lipid intakes of 3-4 g/kg/day and sufficient carbohydrate to meet a total energy intake of 90-110 kcal/kg/day. Where PN is the sole source of nutrition, careful attention to micronutrient requirements is necessary. PN may be administered via peripheral venous access if the osmolality allows, but in many cases requires central venous access. Standardized PN bags may meet the nutrient needs of many preterm infants over the first few days, although restricted fluid intakes mean that many receive inadequate amounts especially of amino acids. PN can be associated with increased rates of bacterial and fungal sepsis, mechanical complications related to venous line placement and miscalculations and errors in manufacture, supply and administration. PN is also associated with metabolic derangements, hepatic dysfunction, and risks contamination with toxins such as aluminum, which enter the solutions during manufacturing. PN must only be administered in units with good quality control, strict asepsis in manufacture and administration and multidisciplinary teams focused on nutrient needs and intakes. © 2014 S. Karger AG, Basel.