The experiment was carried out on 95 samples of the longissimus dorsi muscle (LD). They were collected from carcasses classified to meatiness classes E, U and R (24, 52 and 19 samples, respectively) of pure-bred pbz porkers, hybrids of white pigs sows (wbp x pbz) with Pietrain boars and those of Dutch pigs (Landrace x wb) x wb. After slaughter, blood samples were collected in porkers for DNA analysis to identify animals carrying a stress-susceptibility gene (RYR1). After carcass cooling, meat quality detailed evaluation (dissection) was carried out according to methods given by Walstra and Merkus [1996], on the grounds of which carcasses were classified into respective EUROP system classes. Meat quality was determined as well, pH₁, pH_k and electric conduction; meat colour, wateriness, hardness and consistency were assessed. Moreover, a measurement of the volume of free drip was made, meat wateriness was determined, as well as drip index and colour parameters were calculated. Also, meat basic chemical composition and meat water-soluble protein content were analysed. Furthermore, the frequency of meat with PSE and DFD defects was also determined. Carcasses of porkers from class E and U more frequently showed an incidence of meat defects of PSE, partial PSE and partial DFD types. Higher frequency of the incidence of normal meat was found together with an increase in carcass meatiness. All carcasses of animals with recessive homozygote genotype (nn) had the highest meatiness (classes E and U). The genetic vulnerability of the porkers to produce PSE meat was found in 25% of the studied material. In the group of porkers with the highest meatiness, class E, only 17% (out of 17 animals with genetic burdens 11 nn and 6 Nn), or 3 individuals were found after slaughter to have PSE meat.