Abstract: Objective: To study effects of preoperative chemotherapy on postoperative local recurrence rate of stage Ⅲ breast cancer.Methods: The patients with breast cancer of stage Ⅲ were studied with randomized control assay and were divided two groups(preoperative chemotherapy group and non-preoperative chemotherapy group).In preoperative chemotherapy group,CMF(CTX+MTX+5-Fu) was given once a week and altogether 4 times;after 1 to 2 week,radical operations were performed;the postoperative treatment were carried out according to pathological diagnose.In nonpreoperative chemotherapy group,the treatments were identical except that the patients did not receive preoperative chemotherapy.Results: There was significantly difference between two groups of stage Ⅲ in local recurrence rate(P<0.05).The local recurrence rate was lower in the patients of preoperative chemotherapy.Conclusions: Preoperative chemotherapy is essential for the patients with breast cancer of stage Ⅲ.