Presence or absence of lymph node metastases is the most accurate prognostic indicator in breast cancer. Clinical examination is unreliable in detecting involved nodes. Preoperative ultrasound scan of the axilla has been performed in 140 consecutive women with breast cancer. The sensitivity for involved nodes was 66% which was significantly higher than clinical examination (42%) (P = less than 0.01). However ultrasound gave more false positives than clinical examination and thus no overall improvement in prognostic information was achieved.