The genotoxic properties of three new azoloazine derivatives (azoloazines 1-3) exhibiting cytotoxic activity were studied in an in vitro experiment using human breast cancer cell culture MCF-7. A comparison of the effect of azoloazines 1-3 at a dose of 1/2, 1/10 and 1/50 IC50 with that of epirubicin at the same doses on the main indicators of damage to the genetic apparatus of cells revealed that the substances under study have the greatest toxic effect on DNA at a dose of 1/10 IC50. It is shown that the genotoxicity of azoloazines 1-3 at a dose of 1/10 IC50 exceeds the effect of epirubicin.