BACKGROUND Stereotactic needle biopsy technique has received considerable attention as a possible alternative to surgical biopsy of nonpalpable breast lesions. The exact role of this procedure in the management of mammographic breast lesions has not yet been accurately defined. METHODS Data have been collected prospectively on 416 patients over an 8-month period (January 1992 through August 1992). Of 416, 356 patients underwent only stereotactic breast biopsy with a 14-gauge needle. Sixty patients underwent stereotactic breast biopsy followed by surgical biopsy. Based on mammographic findings before biopsy, lesions were classified as benign (24%), likely benign (49%), malignant (2%), likely malignant (6%), and indeterminate (19%). The number of core biopsy specimens obtained from each patient ranged from one to six. RESULTS The specimen was considered adequate in 98% of cases. Complications were minimal. The tissue diagnosis was benign in 92% and malignant in 8% of patients. In those patients undergoing surgical and stereotactic biopsy, 57 of 60 had matching histopathological results, representing an agreement rate of 95% (p < 0.001). The three patients whose histopathological results did not match had malignant diagnoses on stereotactic biopsy that were subsequently not identified in the modified radical mastectomy specimen because the entire focus of malignancy was removed by the several passes made by the core needle during biopsy. No patient had a negative stereotactic biopsy result in whom malignancy was later detected by surgical biopsy. CONCLUSIONS This study indicates excellent agreement between surgical and stereotactic needle biopsy findings. Stereotactic biopsy with a 14-gauge needle could obviate the need for surgical biopsy in certain women with radiologically benign, likely benign, and indeterminate lesions.