This study compared obese children's food group intakes with the new Dietary References Intakes for Koreans (KDRIs) food guides for 5th-6th grade school children. This study also determined the extent of sedentary life styles related with obesity in this area of children. This is it cross-sectional study of 799 school children. The dietitian sent a survey form describing the project and a questionnaire to the subject's family. The questionnaire included child demographics, family history of chronic diseases, the daily servings of five food groups, such as grains, meat and beans, dairy products, fruits, and vegetables. The daily or weekly hours of physical activity, television viewing, and computer usage were also surveyed. Obesity index (%) of the subjects was calculated, and children with an obesity index (%) equal to or greater than 20 were classified as the obese. Among the 799 participants, 50.7% were female. The percentages of the normal and the obese were 691 (86.5%) and 108 (13.5%) respectively. Obese children reported eating less vegetables (p<0.05), more high sugar snacks (p<0.05), and high fat snacks (p<0.05) than normal children. No significant differences in food servings of grains, meats and beans, and fruits, and dairy products between the normal and the obese were shown. Obese children reported fewer hours of physical activities (p<0.05) and more hours of computer usage (p<0.05) than normal children. Girls showed less likelihood of being obese (odds ratio, 0.575, CI (0.38, 0.87), p<0.05). More hours of physical activity significantly decreased the likelihood of being obese (odds ratio, 0.572, CI (0.35, 0.92), p<0.05). Family history of obesity almost doubled the likelihood of obesity in children (odds ratio, 2.653, CI (1.660, 4.241), p<0.05). In conclusion, frequent snacking, inadequate vegetable consumption, and sedentary lifestyle increased significantly the likelihood of obesity in children, which suggest that obesity intervention in this age group should focuse more on those variables.