The MyoD family genes were considered as candidate genes for growth rate and carcass meatiness in pigs. Gene mutations (SNPs, single nucleotide polymorphisms) discovered in the coding and 5’-flanking regions of the MYOD1 and MYF5 were analysed as possible causal mutations for these traits. Studies of the relation between polymorphisms in both those genes and productive traits were performed on Polish Landrace and Polish Large White gilts. A total of 401 animals (185 Polish Large White and 216 Polish Landrace) was encompassed by the analyses. Homozygotes of the “wild” allele as regards all three mutations of the MYOD1 taken into consideration in the present study appeared to be more profitable for traits characterizing carcass meatiness than the two remaining genotypes. In turn, heterozygotes for mutations identified in the MYF5 gene proved to be most favourable in terms of carcass meatiness. The effect of MyoD genotypes on performance traits was observed to be similar irrespective of the animals’ breed. This may suggest that new mutations, identified in the coding and 5’-flanking regions of MYOD1 and MYF5 genes, could be more useful for selection than the earlier known mutations in the non-coding regions of these genes. In our opinion, two mutations identified in exon 1 of the MYOD1 gene could be most beneficial and useful in selection and breeding of pigs.