Numerous professional organizations have developed position statements declaring breast milk the superior and ideal form of nutrition for full-term neonates. More controversy exists regarding the suitability of breast milk for preterm infants; however, over the past few years there is growing advocacy for providing the preterm infant with his or her own mother's milk whenever possible. This article discusses the unique characteristics of breast milk, issues regarding the use of human milk in preterm infants, and factors affecting the incidence and duration of breastfeeding in the United States and how health care providers can influence them.