The incidence of metabolic bone disease (MBD) in preterm infants has been declining due to advances in nutritional care. Although the terms osteopenia and rickets have been used in the literature, MBD of prematurity is the preferred terminology for this condition. Despite the use of human milk fortifiers and commercial infant formulas specified for this population, MBD remains an important cause of morbidity in preterm infants. This review focuses on the physiology of intrauterine bone growth, the development of MBD in preterm infants, the various risk factors for MBD, pitfalls in diagnosis, prevention, and treatment of MBD. The use of speed of sound (SOS) ultrasonography and dual-energy X-ray absorptiometry (DXA) in the diagnosis, management, and prognosis also is discussed.