The aim of this study was to evaluate the value of ultrasound (US)-guided axillary lymph node fine needle aspiration cytology (FNAC) in staging clinically nodenegative invasive breast cancer. Based on retrospective data, we analyzed sensitivity, specificity, and positive and negative predictive value and efficacy of preoperative axillary US-guided FNAC. A total of 108 consecutive female patients with histological-confirmed invasive breast cancer between January 2006 and December 2010 were included. The management decisions were based on cytological results. Twenty-two patients underwent neoadjuvant chemotherapy and 86 remaining patients benefited of primary surgery. Patients with positive cytology or included in neoadjuvant regimens were scheduled for axillary lymph node dissection (ALND), while patient with negative or nondiagnostic cytology underwent sentinel lymph node biopsy. Axillary US-guided FNAC was compared with definitive pathology of surgically removed lymph nodes. Axillary metastases were found in 55 out of 108 patients (50.9%). In these cases we proceeded with ALND. Excluding the group benefiting from neoadjuvant chemotherapy, we could spare a second surgical intervention for 37 out of 86 patients (43%). The axillary US with FNAC has a sensitivity of 73%, a specificity of 85%, a positive predictive value of 89%, and a negative predictive value of 66%. Without taking into account the neoadjuvant chemotherapy group, in which the statistical analyzes might be biased by the complete histological response, specificity and positive predictive value increased to 100% and negative predictive value to 71%. US combined with FNAC of axillary lymph nodes is a simple, minimally invasive, and reproducible diagnostic approach in improving the preoperative axillary staging of invasive breast cancer patients.Keywords Invasive breast cancer . Axillary node ultrasound . Axillary node cytology . Sentinel lymph node Background and objective