Given its unique nutritional and functional advantages, human milk (HM) should be considered as the first choice for the nutrition of all infants, including preterm newborns. Since its protein, mineral and energy contents are not suitable to meet the high needs of very-low-birth-weight (VLBW) infants, HM should be fortified for these components. Fortification of HM is an important nutritional intervention in order to provide appropriate nutritional intake and appropriate growth. The standard fortification strategy has yielded inadequate protein intakes, resulting in slower growth as compared to preterm formulas. Improvement of outcomes depends on new fortification strategies, considering the large variability of HM composition. Individualized fortification, either targeted or adjustable, has been shown to be effective and practical in attaining adequate protein intakes and growth.