OBJECTIVES: To evaluate the correlation between the pathological findings of stereotactic core needle biopsy (SCNB) and the prebiopsy mammographic findings, as well as the pathological findings of lesions that were subsequently removed by surgical excision. DESIGN: A retrospective review of 97 consecutive patients who underwent 100 SCNBs of suspicious nonpalpable mammographic lesions. The criterion standard is surgical excisional biopsy with needle localization. Mammographic findings were graded according to the American College of Radiology Breast Imaging Reporting and Data System. The pathological findings of SCNB were categorized into 4 groups: benign and specific, benign and nonspecific, premalignant, and malignant. Surgical excision of the lesion was performed if the pathological finding on SCNB was nonconcordant with the prebiopsy mammogram and when premalignant or malignant lesions were found. The pathological findings of lesions that were subsequently removed by surgical excision were compared with those of SCNB. SETTING: Community-based private multispecialty ambulatory practice. PATIENTS: A population-based sample composed of 97 patients who had grade III, IV, or V lesions on routine screening mammograms. INTERVENTION: Stereotactic core needle biopsy of nonpalpable mammographic lesions. MAIN OUTCOME MEASURES: Percentage of patients whose SCNB results were concordant with the mammographic findings and the pathological findings on subsequent surgical excision. RESULTS: Concordance between SCNB and mammography occurred in 97% of biopsy specimens. Concordance between the pathological findings of SCNB and those of surgically excised lesions occurred in 92.5% of biopsy specimens. We had 1 false-negative result. We had no false-positive diagnosis of cancer with SCNB. CONCLUSION: On the basis of accumulating literature and our own initial experience, SCNB is a promising, safe, and cost-effective procedure.