The purpose of the work was to analyze the frequency of chromosomal instability in different species of agricultural animals in Western Siberia on the basis of literature data. The analysis of the literature on the topic of somatic chromosomal instability in agricultural animals has been carried out. Despite the stability of the chromosome set, deviations from it are quite common. It is noteworthy that chromosomal instability is characteristic of almost all individuals in the population and serves as an important indicator for assessing the natural mutability of chromosomes. It has been found if an aberration appeared in one tissue, it is very likely to occur in others. It has been noted that somatic chromosomal instability occurs in animals with reduced reproductive function, as well as those suffering from any pathology. For example, in calves with parakeratosis the increase in the frequency of chromatid and isochromatid breaks has been found. Analysis of the frequency of aberrations in sires, which differ in the level of perinatal mortality of offspring revealed the increased percentage of offspring mortality in fathers with the large number of chromosomal disorders. Therefore, low fertilization, spontaneous abortions and stillbirths may be indications for karyotypic analysis. It has been revealed that the lability of the karyotype is inherent in all animal species, regardless of the species, sex and age, as well as the morphofunctional state. The data on some types of somatic chromosomal instability in different types of farm animals in Western Siberia has been presented. Such indicators as the frequency of polyploidy, the number of cells with fragments of chromosomes, as well as single and paired fragments of chromosomes has been given. Different types of chromosomal instability varied depending on the animal species and climate zone. The presented data can be accepted as a physiological norm and used in veterinary medicine and animal science.