The purpose of this study was to investigate the prevalence of obesity in urban and rural junior high school students. Height, weight, skinfold thickness and bioelectrical impedance were measured. The results obtained were summarized as follows : The average height and weight of boys were respectively 159.61cm 50.56kg and those of girls were respectively 155.88cm, 48.12kg. The percentage of obesity was respectively 6.20%, 10.22%, 5.47%, 17.15%, 14.60% for boys and 4.38%. 9.69%, 3.13%, 3.75%, 7.19% for girls by BMI, RI. OI, % body fat I, % body fat II. The rates of obesity were higher in boys than in girls, so nutritional education on obesity for boys is especially necessary. 21.09% of boys and 7.04% of girls in urban and 7.09% of boys and 7.48% of girls in rural were obese. Correlation coefficients between TC(triceps skinfold thickness + calf skinfold thickness) and BMI, RI, OI, % body fat I and % body fat II were 0.66, 0.67, 0.67, 0.77, 0.70.