Human milk is the preferred feeding for both term and preterm infants. While being considered optimal for term infants, human milk, even from mothers delivering preterm infants, is lacking in protein, energy, sodium, calcium, and phosphorus, resulting in poorer growth and nutrient deficiencies when compared to formulas designed for these high-risk infants. Further, the lack of growth is associated with long-term adverse consequences. Since human milk has unique properties in promoting gastrointestinal maturation and immunological benefits, it is prudent to implement strategies to fortify it appropriately to realize its benefits which include reduced rates of necrotizing enterocolitis, fewer episodes of sepsis and urinary tract infections, and improved visual and neurocognitive development. Donor human milk is being widely used when mothers' own milk is not available or is in short supply. While it retains some of the biological properties and clinical benefits of mothers' own milk, it requires additional care in fortification, especially if the donor milk is from a pool of term human milk. As nutritional strategies improve, the ultimate goal is to minimize extrauterine growth restriction and promote appropriate growth after regaining birth weight.