This study was undertaken to compare the obesity related dietary factors among rural middle school students living in Korea. Anthropometric data showed that mean height and weigh were 161.7+/-13.0 and 49.8+/-10.3kg in 226 male students and 158.3+/-6.1 and 48.2+/-7.5kg in 212 female students. Mean BMIs for boys and girls were 19.10+/-2.47 and 19.26+/-2.35, respectively. 71.68% of male students and 72% of female students were underweight by the BMI index. The BMI of older students was higher than young ones in both sexes. Most nutrient intakes of the subjects were below the RDA. In particular Ca and Fe intakes were extremely low in both sexes. 66.88% of the students skipped breakfast and it was found that the reasons for missing a meal for both sexes were significantly different. Compared to males, more female respondents felt guilty and depressed related to eating. Furthermore, females were more significantly concerned with body image, diet, and body weight(p<0.001), and they were not satisfied with their weight. The sources of information on obesity and diet were from radio and TV in males while females got information from magazines and friends. In male students their ideal body weight was higher was higher than actual body weight. In contrasting, female students desired a thin body shape. A different approach for nutrition education for adolescents should be developed and implemented based on sex.