Animals breeding with a strong constitution and good adaptability to the environmental and forage conditions of rearing zone is crucial (or critical) in increasing meat productivity. The aim of our research was the morphological characteristics of Aberdeen Angus cows and heifers in relation to C528T and C73T polymorphisms of leptin gene. The objects of the study were cows after the first calving (n = 50) and heifers at the age of 20 months (n = 49), which were grouped by the genotype for leptin gene and polymorphisms C528T and C73T. Genetic variability of Aberdeen-Angus cows and heifers by leptin gene was associated with the morphological characteristics of the mature herd. The LEP C528T polymorphism in heifers had a significantly greater effect on the variability of live weight and body size. The heterozygous variant was more preferable for selection and breeding work aimed at increasing the massiveness and size of meat herds.