A review of publications is presented on the diversity of myostatin gene polymorphisms in farm animals. The quality indicators of animal carcasses largely depend on many factors, of which the genotype of the individual plays an important role. Myostatin (MSTN), or growth/differentiation factor 8 (GDF-8), is a protein member of the transforming growth factor (TGF-β) superfamily. The MSTN protein sequence includes a secretion signal sequence, a proteolytic processing site, and a carboxy-terminal region with a conserved pattern of nine cysteine residues. The main function of myostatin is to inhibit the growth of muscle fibers. Myostatin regulates muscle development at key moments in the intrauterine development process: proliferation of muscle precursors, proliferation and differentiation of myoblasts. Myostatin expression is most intense in skeletal muscle tissue. Many farm animals have mutations associated with decreased myostatin activity, of which the most pronounced example is double muscle in some beef cattle breeds. In general, mutations in the myostatin gene lead to a qualitative and quantitative increase in muscle mass in meat breeds of farm animals, as well as changes in other characteristics that depend on muscle mass, such as running speed in dogs and horses. The negative consequences of mutations in the myostatin gene include cancer, premature aging, dystrophy, etc., to prevent which heterozygotes are usually given preference in selection.