Abstract: Objective To assess the correlation between factors for metabolic syndrome and risk of breast cancer in Chinese women. Methods A large scale epidemiology investigation of breast cancer was carried out in communities of 4 Beijing districts by our department from 2011 to 2012. One hundred and sixteen breast cancer patients served as a breast cancer group and 348 age-matched non-breast cancer subjects served as a control group in this study. Their BMI, WC, serum levels of FBG, OGTT 2h blood glucose, HbA1c, TG, HDL-C, and blood pressure were measured. Results The serum levels of OGTT 2 h blood glucose and HbA1c were significantly higher in breast cancer group than in control group (9.46±3.88 mmol/L vs 8.44±3.55 mmol/L, 6.33%±1.07% vs 6.07%±0.88%, P=0.01). The risk of breast cancer increased with elevated serum OGTT 2 h blood glucose and HbA1c levels (OR=1.07, OR=1.30). The proportion of breast cancer patients with their OGTT 2 h blood glucose ≥ 7.8 mmol/L and HbA1c ≥ 6.5% was significantly higher than that of controls (57% and 29% vs 41% and 20%, OR=1.80, OR=1.83, P=0.008, P=0.01). Conclusion Metabolic syndrome, especially the OGTT 2 h blood glucose and HbA1c level, increases the risk of breast cancer.