In this study, we have assessed the association between three genetic variants of the UCP2-UCP3 gene cluster, the -866G/A (rs659366) and the 45bp insertion (in position 173247 of the AC019121) of the UCP2 gene, the -55C/T (rs1800849) polymorphism of the UCP3 gene and their estimated haplotypes with childhood obesity and insulin resistance.