Aims: This study aims to investigate whether the use of hormonotherapy pharmaceuticals causes metabolic syndrome-like symptoms in patients diagnosed with breast cancer and to compare the long-term effects of the drugs. Methods: This retrospective file analysis was conducted on breast cancer patients who presented to the Radiation Oncology clinic between January 2019 and April 2022. Files of 75 patients diagnosed with breast cancer, postmenopausal, and without any previous chronic diseases such as diabetes or hypertension were included in the study. Patients who were started on medications with different active ingredients (tamoxifen citrate, letrozole or anastrazole) in the adjuvant period were examined in 3 groups. Waist circumference thickness, body weight, blood pressure, and blood biochemical tests (blood glucose, lipid levels) were measured before and 6 months after the start of the drugs, and the values were compared retrospectively. Results: Of the 75 patients included in the study, the average age of patients using tamoxifen was 59.6; The average age of patients using letrozole was 59.12 years and the average age of patients using anastrozole was 63.56 years. There was an increase in fasting blood sugar (p:0.014) and waist circumference (p:0.009) in the tamoxifen group. There was an increase in fasting blood sugar, weight, waist circumference, blood pressure and lipid levels in the letrozole and anastrazole arms (p<0.0001 for all). Furthermore, comorbidities such as diabetes mellitus and hypertension that developed after using drugs were ascertained. Conclusion: We think that there is a significant association between hormonotherapy medicines used in breast cancer and metabolic syndrome. While we found increases in blood lipids, FBG, body weight, and waist circumference in most of the patients, we observed that these increases were significantly higher in the groups using aromatase inhibitors. These patients should be examined in detail before starting hormone therapy. Diet, active lifestyle, and sports should be recommended.