Purpose : To evaluate morphologic characteristics of the microcalcifications on mammography that wereconfirmed pathologically. Materials and Methods : Forty five cases of microcalcifications on mammography (fifteencases of benign lesion, thirty cases of malignancy) were retrospectively reviewed. Results : The number ofmicrocalcifications within 1 cm2 were more than 5 in 22 cases (73%) of 30 malignancy and less than 5 in 11 cases(73%) of 15 benignity. The heterogeneity of microcalcifications were seen in 26 cases of malignancy (87%) and thehomogeneity of microcalcifications were 11 cases of benignity (73%). The morphologic characteristics of themicrocalcifications were linear-V shape in 9 cases (30%), punctate shape in 8 cases (27%), fine stippled shape in7 cases (23%), and round dot shape in 6 cases (20%) of malignancy and, round dot shape in 11 cases (73%), punctateshape in 2 cases (13%), and linear-V shape in 2 cases (13%) of benignity. Conclusion : Numerous irregularmicrocalcifications that are heterogenous in size and morphology were strong indicators of malignancy.