The micronucleus (MN) test is a common tool used to evaluate cellular genetic instability at the chromosomal level. It determines the effect of physical, chemical and environmental factors on DNA, and thus the body's individual resistance to harmful substances. The karyotypes of blue and silver foxes and their interspecific hybrids are characterized by morphological and structural variation. This variation is partly attributable to the presence of chromosomal polymorphism, which may significantly influence the stability of genetic material in the cells of these species. The objective of the study was to evaluate genetic material stability in selected Canidae species. To this end, analyses using the MN test were performed. Binucleated cells (BNCs) were analysed in microscopic preparations, and the number of micronuclei was determined within these cells. For the proportions of both MN and BNCs, highly significant differences were observed between the fox species. The interspecific hybrids differed from the other fox species in MN percentage. The lowest average was noted in blue foxes (3.33) and the highest in interspecific hybrids (15.21).