BACKGROUND Pathologic evaluation of sentinel lymph node biopsy (SLNB) samples is crucial for axillary staging in patients newly diagnosed with breast cancer. Patients with pathologic evidence of nodal metastasis scheduled for upfront surgery typically also undergo axillary lymph node dissection (ALND). Although SLNB is the gold standard method for detecting nodal metastasis, axillary lymph node fine-needle aspiration biopsy (FNAB) utility has not been thoroughly explored. METHODS Ultrasound-guided axillary lymph node FNAB samples along with concurrent ipsilateral breast tissue samples were searched and reviewed. The control group included histologic findings of axillary dissection or intraoperative SLNB results. RESULTS A total of 354 axillary lymph node FNAB samples with matched histology were included. Of these, 187 (52.8%) were positive for metastatic carcinoma of breast origin; 143 (40.4%) were negative for metastasis; 12 (3.4%) showed atypical cells; six (1.7%) were suspicious for metastasis; and six (1.7%) were nondiagnostic because of a lack of lymphoid tissue and malignant cells. Of the 143 negative FNAB samples, 22 (15.4%) were positive on either intraoperative SLNB or ALND. When only the positive and negative FNAB samples were accounted for (n = 330; 93.2%), overall diagnostic sensitivity and specificity were 89.4% and 99.2%, respectively. CONCLUSIONS Although axillary SLNB is the standard procedure for detecting nodal metastasis of breast origin, axillary lymph node FNAB appears to be a suitable alternative in a significant proportion of patients. A standard SLNB should be performed in cases of negative axillary lymph node FNAB findings, particularly nodes with abnormal imaging findings.