The purpose of this study was to implement and evaluate the nutrition education program for elementary school children Subjects were 5th graders (n = 142) of an elementary school in Seoul, and 138 children completed four sessions of nutrition education during March-April, 2008. One group pretest-posttest design was used to evaluate the program effectiveness. Anthropometric measurements and measurements on nutrition knowledge, eating attitudes and eating behavior were done before and after education. Data were analyzed using paired t-test, t-test and ${chi}^2-test$. After completing nutrition education, body mass index (from 19.3 to 18.9), fat mass (from 10.9 kg to 10.1 kg), percent body fat (from 25% to 23.3%) of subjects decreased significantly (p < 0.001). Percentages of overweight or obese children were 24.6% at pretest and decreased to 20.3% at posttest, although it did not reach statistical significance. Total score of nutrition knowledge increased significantly from 11.9 (59.5/100) at pretest to 14.7 (73.5/100) at posttest (p < 0.001). After nutrition education, percentages of correct answers increased significantly in 10 knowledge items out of 20 items. These included items such as desirable weight control, energy requirements for boys, food groups, snack, and function of fat and balanced meals (p < 0.001). Total score of eating attitudes increased significantly from 35.1 to 36.9 (p < 0.001). Attitude of applying nutrition knowledge to daily life (p < 0.001), interest toward nutrition and health (p < 0.001), attitude of moderating food intake (p < 0.01), and attitude toward eating habit and future health (p < 0.05) were significantly different between pretest and posttest. Total score of eating behaviors increased significantly from 46.7 (possible score: 20-60) to 49.5 by nutrition education (p < 0.001). Improvement in eight eating behaviors were noticed after nutrition education. These included eating meals slowly, eat protein foods (p < 0.001), eating breakfast, eating meals regularly, eating meals with diverse foods, having dairy foods, eating foods using plant oils (p < 0.01), and having grains (p < 0.05). Subjects evaluated quite positively in attractiveness of program, understanding of program contents, helpfulness of program in improving nutrition knowledge and meal management. Study results show that the nutrition education program was effective in improving nutrition knowledge, eating attitudes and changing eating behaviors of children. This program can be used in nutrition education of children at school or at public health centers.