Hospitalized preterm infants grow slower and have lower bone mineralization than term infants. It has been reported that most preterm infants will catch up to the term infants' bone mineralization by two years of age. The purpose of this study is validate this observation and to evaluate the preterm infants' bone mineralization beyond two years of age. We studied 20 Caucasian children who were graduates from our newborn intensive care unit, and who were born with birth weights less than 1560 g and with gestational ages less than 33 weeks. Fifteen Caucasian children who were delivered at term served as controls. All children were between the ages of 5 to 9 years. The gender distribution between the two groups was similar. All children had their weight and height measured and a 3 day dietary history recorded. The child's lumbar(L2 to L4) spine was evaluated by dual energy X-ray absorptiometry and the distal third radius bone by single photon absorptiometry. Both methods have 1% to 2% error in accuracy. The average age for both groups was similar, 7.6± 1.3 (mean ± SD) years. Both weight (21.8 ± 4.8 kg vs. 22.2 ± 3.9 kg) and height (120.2 ± 9.5 cm vs. 118.9 ± 11.4 cm) measurements were similar between the two groups. The bone mineral content of the radius bone was lower in the preterm group vs. the term group, 0.364 ± 0.063 g/cm vs. 0.574 ± 0.073 g/cm, P<0.06. Lumbar bone mineral density was also lower in the preterm group vs. controls, 0.248± 0.062 vs. 0.574 ±0.073 g/cm squared (P<0.001). Dietary intakes of total calories, protein, vitamin D, calcium, and phosphate were similar in both groups and were within the recommended dietary allowances for children. In summary, children who were born prematurely have similar growth compared to children born at term. But bone mineralization for children born prematurely remains low at 5 to 9 years of age compared to children born at term. We speculate that this lower bone mineralization is due to the child's prematurity and higher calcium and phosphate requirements.