Introduction and objective: The status of regional lymph nodes is one of the most important prognostic factors in breast cancer. Massive extracapsular extension of breast cancer metastasis carries a high risk of disease recurrence. A fairly high rate of false-negative clinical diagnoses of the N trait is observed during preoperative breast cancer staging. This may expose patients to prolonged therapeutic management. In this analysis, it was determined whether there is any correlation between body weight, BMI, age, and axillary fat infiltration in a population of patients who underwent both procedures – sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) – and were not originally suspected of having nodal metastases at all (cN0). Material and methods: The retrospective, one centre, cN0 breast cancer medical records analysis was performed. There were 37 women operated on between 2015 and 2019 for newly diagnosed breast cancer who ultimately underwent both procedures: SLNB followed by ALND as another separate procedure due to axillary node involvement found in the SLNB. The t-test for dependent pairs was used (confidence interval 95%). Results: A statistically significant association (p <0.001) between body weight and axillary fat infiltration was observed, but the linear correlation was not statistically significant. The second association – between age and axillary fat infiltration – was also statistically significant (p <0.001), while the linear correlation was not statistically significant. The association between BMI and nodal axillary fat infiltration was statistically significant (p <0.001), and unlike the previous two variables, the linear correlation was also statistically significant (p = 0.046); Pearson’s correlation coefficient was r = +0.329, indicating a sufficient positive correlation. Conclusions: A statistically significant, sufficient, positive, linear correlation was found between BMI and nodal metastases with axillary fat involvement in women with breast cancer, initially staged as cN0.