Dual energy X-ray absorptiometry DXA was used to follow postnatal changes in the bone mineral content BMC of 20 premature newborn infants with gestational age (32.2 ± 0.90) weeks and birth weight (1.981 ± 0.41)g. BMC was measured once at birth and another when these infants reached maturity by age (38.5 ± 0.17)weeks. Also BMC of an equal number of full term newborn infants was studied at birth. Results of this study showed that: BMC and body weight of premature infants increased significantly at term (45.15 ± 0.31g and 3.250 ± 0.367g respectively) compared with BMC and body weight measured at birth (16.0 ± 0.73 g and 1.981 ± 0.41 g respectively), P <0.007. Also, at term the premature newborn BMC and body weight are still significantly low compared with BMC and body weight of full term newborn infants (56.32 ± 0.39 g and 3.492 ± 0.365 g) respectively for full terms, P<0.001. Serum calcium, phosphorus, alkaline phosphatase and osteocalcin concentrations were not significantly different between the preterm and full term newborn infants at any time point. We can conclude that BMC of preterm newborn infants increased at expected term but is still low compared with BMC of full term infants. This difference may be related to the difference in body size between full term and preterm at expected term.