To investigate the change of perception after weight management education in elementary, middle and high school students, a survey was conducted. Same questionnaire was administered twice, before and after weight management education, to 426 students at 9 schools in Seoul area. The mean height, weight and body mass index were 145.5$\pm$8.0cm, 40.0$\pm$8.3kg, 18.6$\pm$3.0 for elementary school students, 160.1$\pm$5.2cm, 50.2$\pm$7.3kg, 19.5$\pm$2.4 for middle school students, and 162.2$\pm$5.0cm, 52.2$\pm$6.4kg, 19.8$\pm$2.3 for high school students, respectively. Before education, their preferred weight and perceived healthy weight was 35.4kg and 37.0kg among elementary school students, 44.8kg and 46.5kg among middle school students, and 47.3kg and 48.9kg among high school students, respectively. Differences between their present body weight and their preferred weight and/or perceived healthy weight appeared to be 4.5kg and 2.9kg in elementary school students, 5.6kg and 4.0kg in middle school students, and 5.1kg and 3.3kg in high school students, respectively. After administering education, the differences decreased to 2.5kg and -0.2kg in elementary school students, 4.2kg and 2.7kg in middle school students, and 4.3kg and 2.0kg in high school students, respectively (p<0.01). And their perception on own body shape was investigated using 5 point scale ('too lean' to 'too fat', 1 to 5) before and after education. The mean values changed from 3.1 to 2.8 in elementary school students, from 3.3 to 3.0 in middle school students, and from 3.4 to 3.2 in high school students (p<0.01). Their satisfaction with own body weight was monitored using 5 point scale ('very satisfied' to 'very unsatisfied', 1 to 5), also. The mean values changed from 3.0 to 2.7 in elementary school students, from 3.6 to 3.2, in middle school students, and from 3.8 to 3.4 in high school students (p<0.01). In the evaluation of their nutrition knowledge about weight control using 10 item quiz, before and after education, the mean quiz score was changed from 6.3 to 7.0 in elementary school students, from 7.0 to 7.9 in middle school students, and from 7.5 to 8.1 in high school students (p<0.01). In summary, nutrition education on weight management improved the subject's perception on perceived healthy weight and own body shape, and satisfaction with present body weight. This result suggests that nutrition education program should incorporate strategies to change incorrect beliefs and knowledge regarding weight control. Onto this, weight control education for students should start from their early age, be repeated periodically and consistently, and focus on the harmful effects of excessive weight loss and information on the practical and scientific ways of weight management.