BACKGROUND Breast magnetic resonance imaging (MRI) has been recommended increasingly in the preoperative setting for patients newly diagnosed with malignancy to evaluate tumor extent, multicentricity, and contralateral disease. METHODS Results of conventional imaging, breast MRI, and pathology were analyzed from 603 consecutive breast cancer patients who underwent MRI preoperatively. The focus of this retrospective study was imaging-histologic correlation. RESULTS Reoperation for positive margins after lumpectomy occurred in 8.8% of patients. Multicentricity was identified by MRI alone in 7.7% of patients, whereas 3.7% were found to have contralateral cancer by MRI. The sensitivity of MRI was 93% in detecting multicentric disease and 88% for contralateral disease, whereas sensitivity for conventional imaging was 46% and 19%, respectively. Unsuspected disease was identified by MRI equally for invasive ductal and ductal carcinoma in situ histology, whereas multicentricity was found more frequently with invasive lobular carcinoma. CONCLUSIONS Breast MRI is recommended for preoperative evaluation of the newly diagnosed breast cancer patient.