objective: assess the risk of cardiotoxicity of chemotherapy in breast cancer patients and prevention options according to the Nizhny Novgorod Local Register, as well as assess the prevalence of cardiovascular risk factors, cardiovascular status and baseline cardioprotective therapy of patients included in the register depending on the stage of chemotherapy treatment. Materials and Methods: a local retrospective-prospective register of breast cancer patients receiving polychemotherapy has been created. According to the retrospective part from November 2018 to February 2020, 150 high or very high cardiovascular risk patients with breast cancer receiving chemotherapy treatment are included in the register. Follow-up continued for 4 or 8 courses depending on the prescribed chemotherapy regimen. Cardiotoxicity of chemotherapy was assessed by echocardiography and troponin I (TnI) levels. Results: the register was dominated by patients of high (82%) and very high cardiovascular risk (18%). There were also no significant differences in therapy composition at the time patients were included in the register. After 4 courses of polychemotherapy (PCT), 28 patients (18.9%) showed objective signs of cardiotoxicity. In 22 patients (14.8%) — signs of early cardiotoxicity (18 patients — an increase in the level of TnI, 4 — the appearance of diastolic dysfunction after PCT). In 4 patients (2.7%) — the appearance of heart failure (HF) symptoms without reducing left ventricular ejection fraction (LVEF) and increasing biochemical markers. In 2 patients (1.3%), the development of symptomatic HF with low LVEF. During the follow-up in the cardiotoxicity group, cardioprotective therapy was prescribed. Against the background of the prescription of cardioprotective therapy, 16 patients (88.8%) showed normalization of the level of TnI, on average by 6 courses of PCT. Conclusions: breast cancer patients receiving polychemotherapy with anthracycline antibiotics included in the regimen have a significant risk of cardiotoxic effect, especially early biochemical cardiotoxicity. Timely prescription of cardioprotective therapy allows correcting early signs of biochemical carditoxicity and continuing chemotherapeutic treatment.