It is well known that the medullary carcinoma of the breast is one of the special types of breast carcinoma with a good prognosis. At present, the medullary carcinoma of the breast is subclassified into 3 types : typical medullary, atypical medullary and nonmedullary carcinoma. Among them, the former has the best prognosis. We reviewed the fillm mammographic and ultrasonomammographic findings of 13 patients according to the reevaluated histopathologic diagnosis. Typical medullary carcinoma shows a well circumscribed mass with surrounding halo on film mammogram, and well defined mass with central intermediate enchogenicity and peripheral low echogenicity and posterior acoustic enhancement on ultrasonomammogram. Atypical medullary carcinoma shows relatively well circum-scribed mass with partial marginal obliteration on film mammogram, and irregular bordered mass with inhomogeneous echogenicity due to focal necrosis in the mass and associated findings of thick boundary, asymetrical lateral shadowing on ultrasonomammogram,. and irregular bordered mass with inhomogeneous echogenicity due to focal necrosis in the mass and associated findings of thick boundary. asymetrical lateral shadowing on ultrasonomammogram. Nonmedullary carcinoma shows lobulated mass with surrounding parenchymal distortion and skin thickening on film mammogram, and relatively well defined lobulating mass with surrounding parenchymal distortion and marked heterogenous internal echogenicity on ultrasonomammogram. Therefore, differentiation between typical medullary carcinoma with good prognosis and atypical medulary or nonmedullary carcinoma with poor prognosis, may be possible by various diagnostic imaging modalities preoperatively. But, further collective study shall be needed in near future.