Objective:To explore the risk factors of breast cancer among women in Jiangsu Province. Methods:A case-control study and univariate and multivariate logistic regression were employed to evaluate the association of menstrual and reproductive factors with breast cancer in 515 breast cancer cases and 515 controls. Univariate and multivariate logistic regression analysis were carried out with SPSS13.0 software. Results:In the univariate logistic analysis,subjects with elder age at first live birth,menarche ≤15 years,having the history of abortion,and familial history of cancer are the statistically significant risk factors of breast cancer,whereas breast feeding,oral contraceptives are the protective factors. Multivariate logistic analysis also revealed that familial history of cancer and the history of abortion are the risk factors while the breast feeding is a protective factor. Conclusion:Menstrual and reproductive factors and familial history of cancer among women in Jiangsu province are associated with the breast cancer.