The authors reviewed mammograms and/or ultrasound (US) scans of 76 lesions (67 patients) suspected of being recurrent breast cancer. All patients had previously undergone mastectomy. Sixty-one cases were malignant disease and 15 were benign. Mammography and US were complementary to clinical examination in evaluating palpable lesions at the mastectomy site. Both imaging methods revealed nonpalpable recurrences. The sensitivity of US was 91%, whereas the sensitivities of clinical examination and mammography were 79% and 45%, respectively. US was the best imaging method for evaluating tumors in the chest wall far from the scar and in the axilla, as these could not be visualized on mammograms. Most recurrent cancers were seen as circumscribed masses at mammography and as hypoechoic lesions at US. Hyperechoic recurrences could not be differentiated from benign lesions. The value of early detection of recurrences with imaging methods remains to be seen.