PURPOSE: We wanted to evaluate the accuracy of sentinel lymph node biopsy (SLNB) in patients with clinically negative lymph node after neoadjuvant chemotherapy. METHODS: Fifty-nine women underwent 4 cycles of neoadjuvant chemotherapy with epirubicin (75 mg/m2) plus docetaxel (75 mg/m2), or with doxorubicin (50 mg/m2), cyclophosphamide (600 mg/m2) and 5-fluorouracil (500 mg/m2) for their primary breast cancer. Their median age was 41 yr (range: 29-62) and all the tumors were larger than 3 cm in maximum diameter. SLNB was performed 3 min after periareolar injection of 1% isosulfan blue dye. All the patients underwent lymph node dissection at the level 1 and 2 axillary areas irrespective of their nodal status. RESULTS: A clinical response after neoadjuvant chemotherapy was observed in 46 patients (88%) and 11 (18.7%) patients had a complete pathologic response. Thirty-five patients (62.7%) underwent breast conserving surgery. The sentinel lymph node was identified in 96.6% and the median number of sentinel nodes was 3 (range: 1-6). The median number of dissected nodes was 14 (range: 11-47). Metastasis to the lymph node was observed in 56% of the patients. The sentinel lymph node was the only metastatic node in 12 patients. Three patients with a negative sentinel lymph node were confirmed to have metastasis to non-sentinel nodes after the final histologic examination (false negative rate: 9.1%). The overall accuracy of SLNB was 94.7%. CONCLUSION: SLNB after neoadjuvant chemotherapy was a safe method in patients with clinically negative lymph node.