The SNP rs662 in the paraoxonase 1 gene (PON1 Q192R) has been associated with obesity, dyslipidemia and cardiovascular risk. In this study, DNA samples of 117 children aged 6 to 12 years from San Luis Potosí, México were genotyped for Q192R polymorphism of the PON1 gene.Genotypic frequencies were determined by allelic discrimination assay by real-time PCR using TaqMan fluorogenic probes. Anthropometry, lipid profile, glucose and insulin were analyzed by genotype.The distribution of allele frequency in the population was Q = 65 and R = 35 following the Hardy Weinberg equilibrium (χ(2) = 3.15, p = 0.076). The Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index showed statistically significant differences among QQ/QR/RR genotypes (p = 0.032). The odds ratio for the carriers of the RR genotype was associated with HOMA-IR corresponding to the 95(th) percentile or higher for Mexican children based on sex and age (OR = 4.68; 95% confidence intervals, 1.23-17.8; p = 0.016). When the absolute mean of HOMAR-IR was set as the cutoff, an increased odds was observed (OR = 6.52; 95% confidence intervals, 1.68-25.3; p = 0.008).According to our results, PON1 Q192R polymorphism is a risk marker for insulin resistance, a pathological factor involved in the development of metabolic syndrome.Copyright © 2015 IMSS. Published by Elsevier Inc. All rights reserved.