The purpose of this study was to investigate the relationship between serum leptin, lipids, bone metabolism markers and nutrient intakes of obese middle-school girls compared to those of normal subjects. Each subject was assigned to either the normal(n=22) or obese groups(n=25) according to their BMI. The subjects were asked for their general characteristics and nutrient intakes using a questionnaire and 24-hr recall method. The serum leptin, lipids and osteocalcin(bone metabolism marker) were measured using blood analyses. The average ages of the subjects in the normal and obese groups were 13.9 and 14.0 years, respectively. The average weight(p<0.001) and BMI(p<0.001) of normal group were significantly lower than those of the obese group. The plant protein intake of the girls in the obese group was lower than that of the normal group(p<0.01). The levels of serum leptin in the obese and normal groups were 18.0 and 10.0 ng/mL, respectively(p<0.001). The serum LDL-cholesterol(p<0.01) and triacylgeride(p<0.05) of the obese girls were higher than those in the normal group. Also, the serum osteocalcin(bone formation marker) in the obese group was lower than that in the normal group(p<0.001). The BMI was negatively correlated to osteocalcin(p<0.001), but positively correlated to the serum leptin(p<0.001). The serum osteocalcin was also positively correlated to the plant protein intake(p<0.05). In conclusion, the excessive increase in weight and % body fat in middle-school students appeared to have a negative impact on bone health. Based on these results, further studies will be needed on the effects of bone metabolism markers, obesity and nutrient intakes for proper bone health.