In 1951 , Leporgne pointed out the special diagnostic importance of punctate calcifications in the diagnosis of breast cancer by mammorgraphy. Calcifications within the breast may occure in both maligannt and benign diseases, the characteristic findings have been reported subsequently by many other investigators. This study was done to reevaluate the significance and diagnostic value of calcification of female breast cancers. The clinical materials were 980 cases of those underwent mamorgraphy, an d76 cases of those histopathologically diagnosis was confirmed . Fine calcifications were radiologically found in 24 cases of these 76. A morphological analysis was made in regarded to the relationship between the calcific particles and various mammary diseases. The results were as follows. : 1. The irregularly fine spiculate and punctate calcifications were found in 11 cases(45.8%) of cancer group, and rather uniformly fine smooth calcification s were found in 14 out of 52 cases (2 .9%) of benign conditions. 2. In cancer group , the calcifications were finely punctate or spiculate in shape and innumerable in number with a tendency toward of densely packed clusters within and adjacent to the lesional areas. No spiculate calcifications were observed in benign conditions. There were, however, no difference in either size or density of particles in both genign and malignant conditions. 3. These fine calcifications of the breast by mammography seem to be a useful marker in localizing so small a lesion as not to be palpable and in obtaining proper biopsy specimen.