This activity helps participants develop a greater understanding of how protein, energy, vitamins, and minerals support growth and development in preterm infants. More specifically, William W. Hay, Jr, MD, and Bethany Hodges, MS, RD, CNSC, discuss the balance of macronutrients in preterm infants, with a focus on the role of protein. The challenges associated with preterm infant nutrition in the neonatal intensive care unit (NICU) and the unique nutritional needs of preterm infants are addressed, along with the implications of suboptimal protein intake on growth and development. Practical recommendations for parenteral and enteral protein intake in the preterm infant are covered, using a collaborative case-based approach. Dr. Hay and Ms. Hodges discuss the protein sources for preterm infants, including mother’s own milk, donor milk, and formula.