The purpose of this study was to examine whether residential region(rural and large urban ommunities) made any differences to the body-mass index of elementary schoolers. which was a measure of the obesity level. The subjects were 800 elementary schoolers in their sixth year. who included 400 children from seven elementary schools in rural communities and 400 children from 28 from seven elementary schools in rural communities and 400 children from 28 elementary schools in large urban areas. The two groups were composed of 200 boys and 200girls respectively. The annual data about their weight and height measured in every April were utilized to calcuate their body-mass index to assess thier degree of obesity. The finigns of this study were as below: 1. The residential region and gender made no significant difference to their body - mass index when they were in their first year and sixth year. But when they were in their second, third, fourth and fhfth years. as the boy elementary schoolers from the large urban communities had significantly higher body-mass index( p<.05, p<.01) 2. The boy and girl elementary schoolers from the rural regions and the girl elementary schoolers from the large urban areas showed a significant increase every year in body-mass index when they were in their first to third years, but these children underwent no significant change afterwards. The boy elementary schoolers from the large urban areas showed a significant increase in body-mass index every year, except for their second- and third- grader days (p<.05, p<.0001). 3. Their body-mass index was significantly correlated to thier school year (p<.0001) The boy and girl elementary schoolers from the rural communities and the girl elementary schoolers rom the large urban regions were apt to be obese when they were in the first to third years, and the boy youngsters from the large urban communities were in the same situation every year, except for their second-and third-grader days. In particular, those who were overweight or obese during the first two or three years in elementary school were highly likely to suffer from obesity with age. Therefore, it\'s requested to pay careful attention to the diet and physical activities of younger elementary schoolers.