The prevalence of obesity by measuring the amount of body fat and its related factors were investigated in 315 high school girls living in Seoul. Average body fat amount and body fat percentage measured by the body impedance analysis were 14.2$pm$5.2kg and 25.9$pm$7.0% respectively. Mean body mass index(BMI) was 2.1$pm$2.7kg/m2 and 6.7% of the subjects showed over 25kg/m2 Correlative analysis reveal that the body fat percentage was significantly correlated to both relative body weight and BMI(r=0.66, P<0.01, r=0.68, P<0.01) Relative body weight of the subjects showed positive correlation to those of their mother and father. It was shown that many students skipped breakfast often and did not have a pleasant meal with enough time. There was no relationship between adiposity and dietary nutrient or energy intake. When subgroups of the subjects attending a non-vocational high school and those attending a vocational or technical school were compared obesity was more prevalent in the former. Therefore the burden caused by preparing the university entrance examination seems to play an important role in fat deposition.