The melanocortin-4 receptor (MC4R) gene codes for a G protein transmembrane receptor playing an important role in energy homeostasis control. In pig a single nucleotide polymorphism c.1426G>A has been identified and associated to average daily gain, feed intake and fatness traits but a lack of agreement on the effects of the gene on carcass traits in different breeds comes out from many studies. In the present study the c.1426G>A polymorphism is analysed in two Italian pig breeds, Large White and Duroc to study the association of the MC4R gene with some carcass traits. The results show that the c.1426G>A polymorphism affects daily gain, feed conversion ratio and ham weight in both breeds, lean cuts in the Italian Duroc and backfat thickness in the Italian Large White. The presence of MC4R mRNA transcript in different porcine tissues was analysed.