"The purpose of this study was to assess and compare physical fitness and dietary life attitude on the levels of BMI and %Fat in fifth-sixth elementary school students. 321 elementary school students were divided into ""normal group"", ""overweight group"" and ""obesity group"" based on BMI and %fat. For cardiopulmonary, strength and power strength of physical fitness by groups depending on the levels of BMI, the NG was the first, the OW the second and the OG the third, and there were statistically significant differences(p<.001). For flexibility, the NG was the first, the OW the second and the OG the third, and there was no a statistically significant difference. For cardiopulmonary and power strength of physical fitness by groups depending on the levels of %fat, the OW was the first, the NG the second and the OG the third, and there were statistically significant differences(p<.001). For flexibility, the NG was the first, the OW the second and the OG the third, and there was a statistically significant difference(p<.001). For strength, the NG was the first, the OG the second and the OW the third, and there was no a statistically significant difference. For regular life of dietary life attitude by groups depending on the levels of BMI, the NG was the first, the OW the second and the OG the third, and there was a statistically significant difference(p<.001). For balanced dietary life and dietary life & heath, the OW was the first, the NG the second and the OG the third, and there were statistically significant differences(p<.001). For regular life and dietary life & heath of dietary life attitude by groups depending on the levels of %fat, the NG was the first, the OW the second and the OG the third, and there were statistically significant differences(p<.001). For balanced dietary life, the NG was the first, the OW the second and the OG the third, and there was a statistically significant difference(p<.01). There were also an inverse relationships between; BMI and %fat, cardiopulmonary․power strength and body composition․dietary life attitude, body composition and dietary life attitude(p<.01). These above results lead that physical fitness and dietary life attitude influence in company with BMI and %fat. Therefore, systemized education and programs should be developed, and it must be adopted for elementary school students’ ideal physical fitness and dietary life attitude both in a school and students’ family. ※ Key words : BMI, %Fat, body composition, physical fitness, dietary life"