Objective — to analyze two preoperative breast cancer (BC) diagnostic methods: fine-needle biopsy followed by cytological examination versus trepanobiopsy with histological examination. Material and methods. Two hundred and nine preoperative breast trepanobiopsy specimens and their impression smears investigated in parallel with cytology were analyzed. Preoperative cytological study of fine-needle biopsy specimens was performed in 384 patients with BC. Routine and liquid cytological diagnostic methods, immunocytochemical and histological examinations of trepanobiopsy specimens were used. Results. Cytological and histological diagnoses agreed in 205 (98%) of the 209 cases and did not in 4 (2%). Preoperative histological examination of trepanobiopsy specimens showed a sensitivity of 98%, a specificity of 99%, an accuracy of 98%, and an efficiency of 97%; poor materials accounted for 1.4%. During cytological examination of the impression smears of trepanobiopsy specimens, its sensitivity, specificity, accuracy, and efficiency were 99.3, 97.1, 98.8, and 94.3%, respectively; poor materials were 4.5%. During preoperative fine-needle biopsy followed by cytological examination, its sensitivity, specificity, accuracy, and efficiency were 97.9, 97.6, 96.3, and 87.4%, respectively; poor materials were obtained in 8.6%. The agreement rates of immunocytochemical and postoperative immunohistochemical studies were 88.3% for estrogen and progesterone receptors and 93.2% for HER2/neu oncoprotein. The HER2 gene amplification data obtained from FISH study in BC completely correlated with the immunocytochemical determination of HER2/new oncoprotein. Conclusion. Trepanobiopsy followed by histological examination of its specimens and cytological study of their impression smears may be recommended to enhance the efficiency of preoperative morphological diagnosis of breast diseases.