Objective To investigate the value of combined detection of CA27-29 and CA15-3 in early diagnosis of breast infiltrating ductal carcinoma. Methods The study included 41 patients with breast infiltrating ductal carcinoma and 33 patients with benign breast disease. 35 healthy volunteers were served as control group. The serum levels of CA27-29 and CA15-3 in all cases were examined by IRMA and CMIA respectively. Results The serum levels of CA27-29 and CA15-3 in patients with breast infiltrating ductal carcinoma were significantly higher than those in patients with benign breast disease and control group (P<0.05).The positive rates of CA27-29 and CA15-3 in patients with breast infiltrating ductal carcinoma were 65.9% and 56.1%, respectively, while the positive rate of combined detection of CA27-29 and CA153 was 80.5%. It indicated that the abnormal expression of CA27-29 was closely related to the occurrence of breast infiltrating ductal carcinoma. Conclusion The CA27-29 could be served as one of tumor markers in breast infiltrating ductal carcinoma. Combined detection of CA27-29 and CA15-3 might be conducive to early diagnosis of breast infiltrating ductal carcinoma.