INTRODUCTION AND AIMS The feasibility, accuracy and clinical significance of sentinel lymph node biopsy for patients with breast cancer after neoadjuvant chemotherapy has not yet been determined. The aim of this study was to investigate these questions. PATIENTS AND METHOD Dual agent-guided sentinel lymph node biopsy with preoperative lymphoscintigraphy was performed on 17 breast cancer patients after neoadjuvant chemotherapy at the Department of General and Thoracic Surgery, National Institute of Oncology, Budapest, from April 2004 to August 2005. Patients with clinically lymph node-negative breast cancer less than 3 cm in size after neoadjuvant chemotherapy were enrolled in the study. RESULTS Lymphoscintigraphy showed no axillary lymphatic drainage in 7 patients (41%), and no sentinel lymph node could be identified during surgery in these patients. Axillary lymph nodes were histologically positive in 6 (86%) out of these 7 patients. Sentinel lymph node biopsy was successful in 10 patients (59%), and in 8 (80%) of them the sentinel lymph node proved to be positive pathologically. False negative sentinel lymph node biopsy did not occur. Axillary lymph node status was histologically positive in 14 (82%) out of the 17 patients. The predictable value of the clinical examination of the axilla after neoadjuvant chemotherapy, for the histological nodal status, was very low. DISCUSSION AND CONCLUSIONS Our sentinel lymph node identification rate is lower than the published average in the literature. This difference can be explained by the differences in the indication for neoadjuvant chemotherapy. Our false negative rate (0%) is, however, significantly better than that of others. On the basis of international experiences sentinel lymph node biopsy after neoadjuvant chemotherapy is technically feasible, but its accuracy is not satisfactory and its clinical significance has not yet been determined. Our success rate is specifically low, which cannot be explained by the lack of practice. Taking the histologically very high axillary positive rate into consideration, sentinel lymph node biopsy has no clinical role in our practice after neoadjuvant chemotherapy.