In the current work, we have performed a genome-wide association study to map the genetic determinants of carcass traits in a Duroc commercial population. Three hundred fifty barrows, with registered carcass phenotypes, were genotyped with the Porcine SNP60 BeadChip of Illumina and association analyses were carried out with the GEMMA software. The proportion of phenotypic variance explained by the SNPs ranged between negligible to moderate (h2SNP = 0.01-0.30) depending on the trait under consideration. We also identified several chromosome-wide significant trait-associated regions (TARs) for ham weight (SSC11: 51-53.2 Mb and 67-68 Mb), carcass weight (SSC11: 66-68 Mb), backfat thickness (SSC12: 37-41 Mb, 51-58 Mb) and lean meat content (SSC13: 34 Mb and SSC16: 62-63.6 Mb and 71-75 Mb). When comparing GWAS data generated in the current work with a set of carcass QTL identified in the same population with a panel of 110 microsatellites, we found a limited positional concordance. As a whole, our results demonstrate the segregation of genetic determinants for carcass phenotypes in a commercial population that has been strongly selected for growth and fatness traits.