Authors retrospectively analyzed ultrasonographic findings of 12 cases of breast carcinomas which were proven pathologically at Yeungnam University Hospital from March 1992 to August 1992. Classically, breast carcinomas were described as irregular and lobulated hypoechoic solid masses with inhomogeneous internal echoes and frequent attenuation of the sound beam. And other additional ultrasonographic findings were echogenic rim, disruptions of superficial layer, microcalcification, skin thickening and so on. In our studies, not all of these findings of breast carcinomas were found in each case, but most of these findings were noted. However, several studies have demonstrated considerable overlap in the ultrasonographic appearance of benign lesions and carcinoma. Thus, accurate sonographic determination of the type of solid mass is not possible with current ultrasonographic imaging techniques and criteria. For more accurate diagnosis of breast lesions, sonographic and other imaging techniques are interpreted together.