Purpose : The purpose of this report is to evaluate the characteristic findings of tuberculosis of the breaston mammogram, sonogram, and CT and to compare the results with the imaging features of non-tuberculous mastitis.Materials and Methods : Using mammograms and sonograms, nine cases of tuberculosis of the breast were evaluated,and for four cases, CT was used. Aspects evaluated were contour, shape and size of the lesion, homogeneity ofinternal content, and extension of the lesion from/to the adjacent organs. Diagnosis was based on aspiration,surgery, and pathologic findings including acid-fast bacillus (AFB) staining. Mammograms and sonograms of 19patients with non-tuberculous mastitis of the breast were reviewed. Results : No cases of tuberculous mastitispresented clinical evidence of acute inflammation such as fever, swelling or skin redness. Nine cases oftuberculous mastitis were seen as a distinct mass on mammogram and sonogram. Four of nine cases (44.4%) showed arelatively smooth peripheral margin on mammogram and a cold abscess form on sonogram and CT. There were other fociof tuberculosis in the chest wall, anterior mediastinum, pleural cavity or lung. Five cases demonstrated as anodular type on US. In the non-tuberculous mastitis group, an abscess with distinct margin or direct contiguitybetween a breast lesion and the adjacent organ was observed neither on mammogram nor on sonogram. Conclusion : Inan afebrile patient, relative homogeneous density with distinct margin in the breast on mammogram and a fistulousconnection or direct continuity between breast abscess form with the adjacent organ on sonogram or CT is acharacteristic feature of the tuberculous mastitis. The cold abscess type is a frequent subtypes of this entity,and must also be included.