We analyzed the clinical features of 30 cases of pure ductal carcinoma in situ (DCIS). And to compare the histologic grading system for DCIS, we graded the DCIS according to the Lagio's, Poller's. Silverstein's and Holland's classification. In order to compare histologic grading and status of biomarkers such as estrogen receptor, progesterone receptor, c-erbB-2, p53 and ki 67, immunohistochemical method for biomarkers was used. The most common pure and mixed type were cribriform and cribriform and micropapillary DCIS, respectively. Distribution of histologic grading according to the Lagio's, Holland's and Silverstein's except Poller's classification were similar, and about 2/3 of cases were high grade. High grade lesions more freguently lack estrogen and progesterone receptors (P<0.05), have overexpression of the c-erbB-2 and p53 (p<0.05). In summery, adequate histologic grading and biomarkers were very important in DCIS.