[en] We evaluated the significance and accuracy of sonographic detection of metastatic axillary lymph nodes (LNs) in breast cancer. We retrospectively reviewed the sonographic findings and postoperative results of axillary LNs in 47 patients with breast cancer. The sonographic criteria for metastatic LNs were defined as the loss of the echogenic hilum and any uneven cortical thickness of over 3 mm. We analyzed the correlation between the preoperative sonographic findings and the postoperative results of the LNs. Out of 47 patients, 22 patients showed 43 sonographic metastatic LNs. Among these 22 patients, 18 patients had 183 histopathologically proven metastatic LNs. The pathological examination of the remaining 25 patients revealed metastatic LNs in 6 patients. The overall sensitivity, specificity and accuracy of ultrasonography for detecting metastatic axillary LNs in breast cancer were 75%, 82.6% and 78.7%, respectively. As the number of metastatic LNs detected on sonography increased, the number of histologically proven metastatic LNs increased. Ultrasonographic evaluation of axillary LNs in breast cancer can provide relatively accurate information about the presence or absence of metastasis. Therefore, it is useful to decide the initial staging and treatment planning of patients with breast cancer