The association was studied between the polymorphism at leptin (LEP), Pit1, and STAT5A loci and meat production traits in 145 Black-and-White growing/fattening bulls. Genotypes of LEP, Pit1 and STAT5A were determined with the PCR-RFLP technique. Over the 8th month of age the 28-day performance test was introduced to assess growth rate and feed conversion during which the fullconcentrate diet was offered ad libitum. At the age of 15 months the bulls were slaughtered, and their carcasses cut and dissected into lean, fat and bone.The allele frequencies were 0.85, 0.07, and 0.08 for A, B and C LEP variants, 0.25 and 0.75 for A and B Pit1 variants, and 0.90 and 0.10 for C and T STAT5A variants, respectively. Polymorphism of lepton significantly affected some carcass traits, and among them the weight of carcass-side that was highest in the AA homozygotes. The effect of Pit1 genotype was observed on carcass dimensions only. The AA homozygotes had higher chest circumference, chest depth, and circumference of round, but BB homozygotes had a higher round width. CT genotype of the STAT5A-encoding gene significantly affected four out of 36 carcass traits measured and was related to higher weight of bone of best + fore ribs (4.2 vs 3.8 kg) and of sirloin (1.6 vs 1.3 kg) as well as to oblique carcass length (140.5 vs 138.5 cm). The CC STAT5A genotype was associated with significantly higher live weight gain from 8 to 15 months (1.04 vs 0,97 kg daily).