There are several metabolic and hormonal disturbances in childhood obesity. The purpose of this study was to determine the relationship between childhood obesity and bone mineral density (BMD), We studied BMD in 37 obese children and in 37 non-obese children. BMD was measured at L-2-L-4 level by using dual energy X-ray absorptiometry. BMD was significantly related to age, height and weight. The mean BMD in the obese children and control group was 0.655 +/- 0.175 and 0.626 +/- 0.159 g/cm(2), respectively, without any statistically significant difference (p>0.05). There was no correlation between BMD values and osteocalcin or calcitonin levels. According to Tanner's pubertal staging, the mean BMD of pubertal obese children was higher than that of prepubertal obese children. BMD or me pubertal obese children was significantly higher than that of the pubertal control group (p<0.05). Girls had higher mean BMD values than boys. In conclusion, our results show that BMD is not influenced by obesity in children but higher values in puberty were observed in obese children which may due to hormonal changes.