The purpose of the study was to examine the effect of a dumbbell exercise program on body composition, bloods lipids and cognitive perceived variables in the obese high school girls with no planned dietary intervention. Forty-four obese high school girls were divided into experimental group(23) and control group (21). Experimental group was adapted to perform the dumbbell exercise program training with intensity of 50-60% HRmax and RPE 11-13, for 40 min/day, 4 times/week during 8 weeks. The data was analyzed using SPSSIPC+ and hypothesis was tested with ANCOVA analysis. The results of this study were as follows : 1. Change in body composition. Body weight, percent body fat, body fat mass in experimental group decreased significantly in comparison with control group(p=.00l). Lean body mass in experimental group increased significantly in comparison with control group(p=.00l). Sum of skinfold thickness in experimental group decreased significantly in comparison with control group(p=.001). 2. Change in blood lipids HDL-C level in experimental group tended to increase, but there was no significant change in comparison with control group. LDL-C, Total Cholesterol, Triglyceride level in experimental group tended to decrease, but there was no significant change in comparison with control group. 3. Change in cognitive perception There was no significant change in perceived benefits on exercise, perceived health status in the experimental group in comparison with the control group. Perceived self-efficacy, emotion on exercise in the experimental group increased significantly in comparison with the control group(p=.010, p=.007). Consequently, it can be concluded that the dumbbell exercise program may be an effective exercise intervention to body composition, blood lipids and cognitive perception of the obese high school girls.