The purpose of the study was to experiment synergy effects of beta3-adrenergic receptor(β3-AR) and uncoupling protein 2(UCP2) gene polymorphism on obesity indices, resting metabolic rate(RMR), and cardiopulmonary fitness. A total of 154 apparently healthy volunteers was recruited via flyers and local advertisements. Obesity indices included body mass index(BMI), percent body fat(%BF), waist circumference, waist/hip ratio. A group having Trp/Trp(TT) homozygotes of β3-AR gene together with Deletion/Deletion(D/D) homozygotes of UCP2 gene showed high mean value significantly in body weight(p=0.004), %BF(p=0.039), BMI(p=0.016), waist circumference(p=0.005), waist/hip ratio(p=0.040), and RMR(p=0.025). And the maximal oxygen consumption per minute low than other groups but it was not significant difference statistically. We think that this synergy effect of β3-AR and UCP2 for obesity indices and RMR made by correlation of these gene and than accumulation of body fat may be accelerated, because a simultaneous mutation of β3-AR and UCP2 bring about not only increasing accumulation of body fat but also decreasing cardiopulmonary fitness by decreasing RMR and fat oxidation. Therefore, the current findings suggest that in the event of mutation of β3-AR and UCP2 simultaneously, morbidity on obesity may increase .