Environmental factors, nutritional supplies, hormonal status, diseases, and treatments appear to affect postnatal skeletal growth and mineralization in VLBW infants. Compared with their term counterparts, ELBW infants are at risk of postnatal growth deficiency and osteopenia at the time of hospital discharge. From recent data, DXA is becoming one of the reference techniques to evaluate mineral status, whole-body composition, and effects of dietary manipulations on weight gain composition and mineral accretion in preterm infants. Weight gain and length increases need to be evaluated carefully during the first weeks of life, in the intensive care unit and out of it, in the step down unit. Nutritional survey is required to improve the nutritional supply and to maximize linear growth. As the critical epoch of growth extends, during the first weeks or months after discharge, follow-up and nutritional support need to be provided during the first years to promote early catch-up growth and mineralization. Further studies need to determine precisely the most optimal feeding regimen during this period but also need to evaluate the long-term implications of such a policy on stature, peak bone mass, and general health at adulthood.