The present study was conducted to investigate the effect of nutrition education program on nutrition knowledge, eating behaviors, food habit, nutrient intakes in obese children and their parents who live in Gumi city. The subjects were 16 obese boys, 20 obese girls with obesity index over 130% and 36 of their parents. The nutrition education for the subjects was carried out by the professional personnel such as doctors, professors, and dietitians. The children were provided with well-balanced lunch meals and had 40 min-lectures on the reasonable weight management, 40 min-games and also had regular exercises (stretching, swimming) for 90 mins everyday during 2 weeks of the program. The parents had 90 min-lectures on childhood obesity, diet therapy, behavior modification, and exercise for 6 times. The nutrition knowledge, eating behaviors and food habits were surveyed by using questionnaires before and after the education. The nutrition intakes of the children were surveyed before and after the education by 3-day food record method. The nutrition intakes of the parents were surveyed before and after the education by using semi-quantity questionnaires. After the education, the mean nutrition knowledge scores were significantly improved compared with the pretest scores in both children and parents. After the education, all subjects' eating behaviors were significantly changed positively and calorie and carbohydrates intakes were significantly decreased and vit. C was significantly increased in obese children. The food habits of the parents were significantly improved after the education. These findings show that the well-designed nutrition education program for obese children and their parents can be an effective approach to help them to improve their nutrition knowledge and to establish desirable food habits and eating behaviors.