The prognostic significance of preoperative carcinoembryonic antigen (CEA) and cancer antigen 15-3 (CA15-3) levels in breast cancer is controversial. This study evaluated the prognostic value of preoperative serum CEA and CA15-3 levels in Chinese breast cancer patients. A total of 470 patients with breast cancer had preoperative CEA and CA15-3 concentrations measured. The relationships between preoperative concentration and clinicopathological factors and outcomes were determined. CEA and CA15-3 levels were increased in 34 (7.2%) and 58 (12.3%) patients, respectively. Elevations of serum CEA and CA-15-3 levels correlated with the primary tumor size and axillary lymph node status. CEA levels were lower in patients with triple-negative breast cancer than in those with other subtypes (P = 0.002). The 5-year distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) of CEA-negative vs. CEA-positive patients were 84.1% vs. 54.5% (P < 0.001), 82.7% vs. 54.8% (P < 0.001), and 89.7% vs. 78.5% (P = 0.007), respectively. The 5-year DMFS, DFS, and OS of CA15-3-negative vs. CA15-3-positive patients were 84.0% vs. 69.6% (P = 0.002), 83.0% vs. 66.2% (P < 0.001), 90.9% vs. 74.2% (P = 0.005), respectively. Multivariate analysis of prognosis indicated that CEA and CA15-3 levels were independent prognostic factors for DMFS (P = 0.021) and DFS (P = 0.032), and DFS (P = 0.014) and OS (P = 0.032), respectively. Serum levels of CEA and CA15-3 may differ in breast cancer molecular subtypes and preoperative levels of CEA and CA15-3 have a significant effect on prognosis in Chinese women with breast cancer.