Polymorphisms MC4R c.1426A>G (p.Asp298Asn) and LEPR c.2002C>T (p.Leu663Phe) have been associated in pigs with feed intake, growth and fatness. Our aims were to analyze how these polymorphisms influence production and quality traits in Duroc×Iberian crossbred pigs, and moreover evaluate how the effects of gender and Duroc line were affecting these traits. Significant effects of gender, Duroc sire line and LEPR c.2002C>T mutation, were detected on the main traits. LEPR c.2002T allele increased body weight (2.5±0.7kg), backfat thickness (1.5±0.4mm), loin intramuscular fat (0.7±0.2 %), and lightness (1.0±0.3); however it was decreasing premium cuts yield (−0.9±0.2%). Allele c.2002T increased SFA (0.60±0.12 %), and decreased MUFA (−0.35±0.12%) and PUFA (−0.25 ± 0.06%). No significant effects of MC4R c.1426A>G SNP were identified. A genetic test based on the LEPR c.2002C>T SNP may be useful to select Duroc sires to reduce undesirable heterogeneity of carcasses and premium cuts of crossbred animals.