The purpose of this study was to evaluate the obesity and weight control prevalence according to the gender and weight control attempt among middle school students in Seoul and Gyeonggi-do, Korea. The mean age of subjects were 14.4 years old. The mean height, weight and BMI value of boy students were 164.0 cm, 53.0 kg, and $19.7kg/m^2$, respectively, and the mean height, weight and BMI value of girl students were 159.4 cm, 49.8kg, and $19.6kg/m^2$, respectively. Both weight and BMI value of the weight loss attempt groups were significantly heavier and higher than those of the other groups (p < 0.01). In the perception on the body image, the girls perceived themselves to be more fat compared to boys, and the weight loss attempt group perceived their body image to be more fat compared to the other groups (p < 0.001). As for the interest degree of weight control, the interest degree of girls was higher than that of boys (p < 0.01). According to weight control attempt, in the order of the weight loss attempt group, the weight gain attempt group and the no weight control attempt group, the interest degree was significantly higher (p < 0.001). In the frequency and hours of exercise, there was significant difference by gender (p < 0.001). According to weight control attempt, the weight gain attempt group exercised more frequently than the other attempt groups (p < 0.01).