BACKGROUND: Axillary ultrasonography (AUS) and fine-needle aspiration cytology (FNAC) can establish axillary lymph node status before surgery, although this technique is hampered by poor adequacy rates. To achieve consistently high rates of FNAC adequacy, rapid on-site evaluation (ROSE) of FNAC samples was introduced. METHODS: This single-centre, retrospective observational study of patients with newly diagnosed breast cancer undergoing preoperative AUS and FNAC between February 2008 and November 2010 examined the effect of the introduction of ROSE. RESULTS: A total of 381 patients were included. AUS revealed 152 axillae with suspicious radiological features. FNAC was positive for malignant cells in 75 (49·3 per cent) of 152 samples. Sentinel lymph node mapping was avoided in 75 patients, representing 19·7 per cent of the entire study population. Adequacy rates increased from 78 per cent to 96 per cent following the introduction of ROSE (P = 0·001). The overall sensitivity and specificity of AUS and FNAC was 80·6 and 100 per cent respectively. A lymph node diameter equal to or larger than 10 mm and extranodal extension were significantly associated with positive FNAC (P < 0·001 and P = 0·012 respectively). Maximum lymph node diameter of at least 10 mm was an independent predictor of positive FNAC (odds ratio 11·2, 95 per cent confidence interval 3·32 to 37·76; P < 0·001). CONCLUSION: AUS with FNAC provided accurate preoperative staging of the axilla for metastatic breast disease and avoided unnecessary sentinel lymph node mapping. The introduction of ROSE ensured the efficiency of AUS and FNAC.