PURPOSE: To analyze and characterize the radiologic findings of lobular carcinoma of the breast, a carcinoma which is very rare in Korea. MATERIALS AND METHODS: Twelve patients with pathologically proven lobular carcinoma were included in this study. Mammography was performed in all patients and ultrasonography in six. Clinical manifestations, mammographic findings and ultrasonographic findings were retrospectively analysed. RESULTS: Mean age of the patients was 45.9 years and the most common clinical manifestation was palpable breast mass (9/12). Radiologic findings of lobular carcinoma were spiculation (11/12), mass density (8/12), asymmetric vessel (6/12), and microcalcifications (6/12). Ultrasonography showed intermediate or lower echoic mass (4/6). Posterior enhancements and shadowings were noted in the same proportion. Breast MRI in two patients showed mass lesion with rapid strong enhancement at 1 minute after contrast injection on dynamic study. Tumor stages were stage II (6/12) followed by stage I (3/12), and most advanced case was stage IIIb. CONCLUSION: On mammogram, the most common finding of lobular carcinoma of the breast was spiculation, and calcifications showed more frequently than in other reports. Ultrasound study showed ellipsoid mass with transverse long axis. Internal echogenicity and posterior sonic enhancement or shadowing of the mass were not characteristic of the tumor.