Vitamin A is a crucial antioxidant for preterm infants because it protects the lungs from oxidative damage induced by the administration of supplemental oxygen. Although all preterm infants are born with smaller vitamin A stores than full-term infants, the store of vitamin A in preterm infants at risk for bronchopulmonary dysplasia (BPD) is often especially deficient. Despite the increases in plasma vitamin A concentrations that have been achieved with vitamin A supplementation, only modest improvements in clinical outcomes and incidence of BPD have been noted in this population. This article reviews the research on vitamin A supplementation for preterm infants, as well as the issues and clinical implications associated with this intervention.