Background: Breast cancer is the most common cancer in women. Its prevalence is increasing annually by 2%. The determination of modifiable risk factors has been the subject of various studies. The aim of this study was to determine risk factors of breast cancer in women in Golestan Province. Patients and Methods: This case-control study was conducted among women with breast cancer recorded in the cancer registry system between 2004 and 2006 (n = 134), and their agematched healthy neighbors (n = 133). Data were statistically analyzed. Results: Age at marriage, menarche and pregnancy, breast feeding, positive family history, marital status, and educational level were not significantly correlated with risk of breast cancer, but age at menopause (< 46.6 years) was significantly correlated (95% confidence interval 1.15–7.37; p = 0.021). Live births, still births, and infant deaths were not significantly different between the 2 groups. For other variables, such as smoking history, no odds ratio was calculated. Conclusion: Results show that there is no significant correlation between variables and risk of breast cancer in our population, except for age at menopause. A large cohort study is recommended.