The investigations were carried out on 120 porkers and included the determination of RYR1 and MYF4 genotypes. The carcasses, dissected according to the Polish Station for Swine Slaughter Performance Inspection (SKURTCh), were evaluated for their meat quality and the occurrence frequency of normal and defective meat. The porkers of a RYR1 genotype TT had higher carcass meatiness and more frequently occurring PSE meat if compared to those of a CC genotype. Heterozygous porkers (CT) showed the highest rate of carcasses with normal meat and a lower rate of carcasses with partially PSE and PSE meat. The MYF4 AA porkers had a better meat quality than those of the AB genotype, as estimated basing on the soluble protein content and dominant wavelength. No RYR1 x MYF4 interactions were found in relation to the majority of meat quality properties and to meatiness in the material analysed.