Breast cancer is the most common cancer in women. Developments in breast cancer treatment have extended the life expectancy of these patients, raising the issue of morbidity of breast cancer surgery, the major cause of which is axillary dissection. The aim of the present study was to establish the safety of sentinel node biopsy (SLNB) in patients with a clinically node-negative axilla after neoadjuvant chemotherapy (NACT). We recorded demographic data, as well as the findings of physical examination, imaging, and pathology before and after NACT. SLNB with indocyanine green + isosulfan blue and axillary dissection were performed and the surgical and pathology findings were recorded. A sentinel lymph node was detected in 80 of 90 patients who underwent surgery. When ≥ three sentinel lymph nodes were removed as negative in the patient group with cN0 after treatment, we evaluated the axilla as being negative with an accuracy of 100%. Axillary lymph-node dissection may not be necessary for patients with cNO confirmed by physical and radiological examination using positron emission tomography (PET) computed tomography (CT), and breast magnetic resonance imaging (MRI) after NACT, if ≥ three negative SLNB are removed. Further studies are needed to confirm our findings.