In neonates born weighing less than 750 g, invasive candidates is common and often fatal. This situation provides an opportunity to study antifungal prophylaxis and treatment in this patient population, in which the pharmacokinetics, safety, and efficacy of antifungal products are unknown. The disease is less prevalent in larger, more mature, infants. Although some pharmacokinetic data for some products are available for term and near-term infants, optimal product choice, closing, and other treatment strategies also are unknown in this older age group.