Abstract: This study was carried out to determine the contribution of body fatness to Bone Mineral Content (BMC) and Density (BMD) in obese children and adolescents. Cross sectional sample of 90 schoolchildren with simple obesity (body mass index ≥95th percentile) and of age range 7.6-16 year participated in this study. Physical examination that included height, weight and pubertal stage assessment in addition to body fat% measurements were performed. Body Mass Index (BMI) was calculated. Regional BMC and BMD were measured by dual-energy X-ray absorptiometry (lumbar spine, proximal femur (neck, trochanter and Ward's triangle). The results indicated a significant effect of adiposity on BMC and BMD observed at all skeletal sites studied. Lumber spine BMC and BMD were greater in girls than boys with significant differences regarding BMC with p<0.01. Body fat % and BMI showed positive correlations with BMC and BMD of spine and hip measurements studied in both sexes. The presence of female sex can predict the increase in spine BMC (p<0.01), BMD (p<0.001), femur neck BMC (p<0.001) and trochanter BMD (p<0.05). The increase in age can predict the increase in spine BMC (p<0.001), BMD (p<0.001), trochanter BMC (p<0.01) and BMD (p<0.01). The progress in puberty stage can predict the increase in spine BMC (p<0.01) and BMD (p<0.05) and trochanter BMC (p<0.001) and BMD (p<0.01). While, height can not predict BMC or BMD of spine or hip measurements. In this population we concluded that, obesity assessed by BMI and body fat % was associated with increased vertebral bone content and density mainly spine and hip. The age, sex and puberty stage were consistent and independent predictors of BMC and BMD in obese children and adolescents. Future studies are needed to determine the effect of these differences on fracture risk and to determine whether the increases in spine and hip BMC are sustained into adulthood.