Stereotactic large-core needle biopsy is increasingly applied for the diagnosis of nonpalpable breast disease. Our study examines whether this minimally invasive technique is sufficiently accurate to replace surgical breast biopsy. In a prospective multicenter study, 973 consecutive women with 1,029 nonpalpable breast lesions were offered stereotactic 14-gauge needle biopsy. If the needle biopsy yielded breast cancer, the patient was offered therapeutic surgery. Surgical biopsy was proposed in cases of needle biopsies without malignancy. An expert panel reviewed all discrepancies in histologic diagnosis between the needle biopsy and open biopsy. Forty-five patients withdrew from participation and 113 (11%) planned needle biopsy procedures were cancelled. Of the 871 successful biopsy procedures, 95% were confirmed surgically. In 13 cases (1.5%), insufficient material was obtained for histologic assessment. Fifty-five percent of the needle biopsies were diagnosed as malignant (290 invasive cancers, 190 ductal carcinoma in situ). Thirteen of the 322 lesions (4%, 95% CI 2-7%) with a benign needle biopsy diagnosis contained malignancy after surgery. Six of the 26 (23%, 95% CI 9 -44%) lesions with a high-risk diagnosis (atypical ductal or lobular hyperplasia or lobular carcinoma in situ) were diagnosed as malignant after surgery. Five of the 30 lesions containing normal breast tissue held malignancy (17%, 95% CI 6 -35%). Guidelines for the management of different categories of needle biopsy diagnoses were made. Application of these guidelines to the present findings resulted in sensitivity and specificity rates of 97% (95% CI 95-98%) and 99% (95% CI 97-100%), respectively. Stereotactic large-core needle biopsy is an accurate diagnostic instrument for nonpalpable breast disease. It may safely replace needle localised open-breast biopsy provided that high-risk and normal breast tissue diagnoses are followed by needle or openbreast biopsy.