OBJECTIVE Fine-needle aspiration and stereotaxic needle core biopsy (SNCB) are techniques used in the workup of breast lesions suggestive of cancer. Many surgeons are reluctant to rely on fine needle results, and until now, SNCB could be done only with a dedicated biopsy table. Our study was done to determine whether SNCB could be performed safely and effectively with a regular mammography unit and an added stereotaxic device. METHODS SNCB was performed on 254 patients by using a Siemens Mammomat 2 regular mammography table with an added stereotaxic device. Patients were referred from a breast screening center, a local tertiary care center, and from our own center. Patients who had unequivocal histopathologic evidence of a benign process (133 of 254 patients) did not undergo surgical biopsy and are being followed up mammographically. The remainder (121 patients) all had surgical biopsies. RESULTS Sufficient material for histologic analysis was obtained in 249 (98%) of 254 cases. In 31 of 254 cases, sampling was problematic. This group comprised cases in which the patient moved within the compression device, the mammographic and histologic diagnoses were discordant, or calcifications were not present in the core sample when the indication for SNCB was the presence of microcalcifications. This group all had open biopsies. In 25 of 254 cases, the pathologic findings were suggestive of cancer. Cancer was detected in 11 of these cases on open biopsy. Of the 14 benign cases, 11 showed atypical features or ductal hyperplasia on open biopsy. Malignant tumor was diagnosed in 60 of 254 cases by SNCB. Corresponding malignant tumor was seen in 59 of 60 of the open biopsy specimens. CONCLUSIONS The SNCB technique is not limited to use on a dedicated biopsy table but can be readily adapted to a regular mammography unit. It is a safe, reliable and cost-effective procedure that often spares the patient a surgical procedure.