The studies were carried out on 158 Polish Landrace fatteners of various HAL genotypes, with average body weight 102 ±5.1 kg and 52.33% of leanness, slaughtered during two seasons: spring and summer as well as autumn and winter. Analysis of variance demonstrated statistically highly significant effect of HAL genotype on all the examined traits. The effect of slaughter season was found for pH24, pH decrease range (pH45pH24) and WHC. In respect to the pH24, statistically significant interaction was found between both factors. Higher incidence of meat with PSE syndrome was observed in the springsummer season (31.33%), which was reflected by more extensive drip loss from the LD muscle. In the group of HALn allele homozygotes, an increase in the dynamics of glycolytic metabolism was observed, especially in relation to the stressresistant (HALNN) group of animals.