Abstract: Objective: To analyze the clinicopathologic features and prognosis of triple negative breast cancer. Methods: A to-tal of 509 cases of operable breast cancer seen in our hospital between January 2002 and June 2002 were analyzed. We used immunohistochemistry to determine Her-2, ER, and PR status. The patients were divided into the triple negative breast cancer group (ER negative, PR negative, and Her-2 negative) and the non-triple negative breast cancer group. The clinicopathologic features of the two groups were compared. The 5-year disease-free survival (DFS) was analyzed by Ka-plan-Meier method. Results: Of the 509 patients, 21.4% (109/509) had triple negative breast cancer and 78.6% (400/509) had non-triple negative breast cancer. The percentage of cases with medullary type or grade Ⅲ was higher in the triple negative group than in the non-triple negative group(P<0.05). No significant difference was found in other clinicopatholog-ic features between the two groups. Till June 2007, local recurrence or distant metastasis was observed in 21.1%(23/109) of the triple negative cases and 12.7%(51/400) of the non-triple negative cases. The rate of local recurrence or distant metastasis in the triple negative group was higher than in the non-triple negative group (P<0.05). The 5-year DFS was 78.9% in the triple negative group and 87.3% in the non-triple negative group(P<0.05). Conclusion: Compared with non-triple negative breast cancer, triple negative breast cancer has an increased possibility of local recurrence or distant metas-tasis, leading to a poorer prognosis.