Abstract: Objective 　To investigate the expression level of cyclinD2 and CDK4 protein in breast carcinoma, and their relationship to p27^kip1protein and clinicopathological factors as well as the prognostic factors in breast carcinoma. Methods 　The SP immunohistochemical technique was used to detect the expressions of cyclinD2, CDK4 and p27^kip1in 96 cases of breast carcinoma and 18 cases of adjacent nontumor normal breast tissue. The relationship between cyclinD2, CDK4 to p27^kip1protein expression and clinicopathological factors were analyzed. Results 　①The positive expressions of cyclinD2, CDK4 and p27^kip1 protein in 96 cases of breast carcinoma were 41. 7 %, 54. 2 % and 38. 5 % respectively. There was a significant difference between carcinoma and normal breast tissue ( P < 0. 001) . ②The expression level of both cyclinD2, and CDK4 protein in breast carcinoma was significantly associated with histological classification, mitotic index, and local recurrence ( P < 0. 05), and little associated with age, tumor size and histological type ( P > 0. 05) . The expression level of CDK4 in breast carcinoma was related to Lymph node metastases and ER status ( P < 0. 01) . ③The loss of p27^kip1protein expression in breast carcinoma was significantly associated with tumor size, histological classification, mitotic index, Lymph node metastases and local recurrence ( P < 0. 05), There was a negative correlation between p27^kip1 and cyclinD2 as well as CDK4 expression in breast carcinoma ( P < 0. 01) . Conclusion 　The expression of cyclinD2 and CDK4 protein may play a important role in the carcinogenesis and progression of breast carcinoma. The loss p27^kip1expression and over-expressed CDK4 was associated with the invasion, metastases and local recurrence, and may be as the indications of biological behavior and prognosis of breast carcinoma.