The investigations included samples of LD and BF muscles obtained from 20 carcasses of hybrid Naïma x P-76 (Penarlan) and Puławska x Polish Landrace (Puł x PL) pigs. The contents of inter muscular fat and the composition of fatty acids in the muscles were determined. It was stated that the content levels of SFA and UFA fatty acids were comparable in the LD muscles of the two genotype groups of pigs. Furthermore, Furthermore, it was proved that the content of saturated fatty acids in the lipids contained in the muscles of BF fatteners ‘Puł x PL’ was by 2.49% lower if compared with the hybrid pigs, and the content of non-saturated acids – by 2.38% higher, Among the nonsaturated fatty acids, monounsaturated acids predominated. However, in the two muscles of the Naïma x P-76 pigs, it was found a significantly higher amount of poly-unsaturated fatty acids, especially C18:2 and C18:3, than in the cross-bred pigs investigated.