AIM: The impact of COVID-19 pandemic is pronounced in each healthcare process, including the management of breast cancer. The anxiety of COVID-19 changes patient preferences and some delay in routine controls and surgical managements occur. Some disintegration in medical care is to be expected during the pandemic, but the new coping strategies are needed in order to avoid delayed diagnosis of breast cancer. METHODS: A total number of 140 patients assigned for biopsy and diagnosed with breast cancer in our tertiary clinic between December 1st and August 31st were classified into 3 groups; A (December-February), B (March-May) and C (June-August) in order to compare the stage of breast cancer at the time of diagnosis before, during and after the peak period of pandemic. Clinical stage and age at presentation, family history of breast, ovarian and other types of cancer, BRCA (genetic testing), menopausal status, side of involvement (uni- or bilateral), histopathologic subtype, receptor positivity and molecular subtype were recorded for each patient. RESULTS: Group A included 20 stage I (27.77 %), 32 stage II (44.44 %), 16 stage III (22.22 %) and 4 stage IV (5.55 %) breast cancer patients. Group B had 5 stage I (22.72 %), 8 stage II (36.36 %), 7 stage III (31.81 %) and 2 stage IV (9.09 %) breast cancer patients. Whereas in group C there were 4 stage I (8.69 %), 21 stage II (45.65 %), 16 stage III (34.78 %) and 5 stage IV (10.86 %) patients with breast cancer. The number of late-stage cancer patients in group C was significantly higher in comparison with the other groups (p<0.05). CONCLUSION: We speculate that the change in incidence of breast cancer by stage is attributable to a delay in the diagnosis of breast cancer due to COVID-19 related restrictions and presentation of new cases at more advanced stages once the restrictions were eased.