Aim. To study the association of rs2232228 (HAS3 gene), rs2229774 (RARG gene), rs1056892 (CBR3 gene), rs1786814 (CELF4 gene), rs1695 (GSTP1 gene), rs8187710 (ABCC2 gene), rs7853758 (SLC28A3 gene), rs243865 (MMP2 gene), rs243866 (MMP2 gene), rs35068180 (MMP3 gene), rs522616 (MMP3 gene), rs679620 (MMP3 gene), rs17576 (MMP9 gene), rs3918242 (MMP9 gene) with the probability of early doxorubicin cardiotoxicity signs in patients with breast cancer of moderate and low HFA-ICOS risk groups.Material and methods. The study included 100 patients (women, over 18 years old) diagnosed with breast cancer who received chemotherapy using doxorubicin.To identify early cardiotoxicity signs, echocardiography was performed before, immediately after and 12 months after the end of chemotherapy. The status of polymorphic variants of the studied genes was determined by real-time polymerase chain reaction.Results. Based on the decrease in global longitudinal myocardial strain (>12%) immediately after and 12 months after the end of chemotherapy, the patients were divided into two following groups: A — early signs of myocardial dysfunction can be diagnosed after the end of chemotherapy (19%); B — early signs of myocardial dysfunction are detected for the first time only 12 months after the chemotherapy end (17%). In patients from category A, a number of allelic variants and genotypes with potential as independent factors for predicting the early signs of myocardial dysfunction were identified, with an emphasis on targets involved in metabolism and detoxification of doxorubicin and its derivatives. In category B, the greatest differences in the frequencies of allelic variants and genotypes were found among target genes encoding matrix metalloproteinases involved in the processes of response to the intensification of oxidative stress caused by doxorubicin and its derivatives.Conclusion. In total, patients in the low- and moderate-risk groups can be divided into at least 2 categories based on molecular genetic testing. For these categories, the development of early signs of doxorubicin-related myocardial dysfunction before the start of chemotherapy can be predicted.