Background and Objectives: Breast cancer is the second most common malignancy which is a life threatening disease among young premenopausal women affecting their sexuality, femininity, body image, and maternal issues following mastectomy may lead the women to face psychiatric co-morbidity.Methods: The data was collected from hospital records, patients documents and annual reports which were verified with respective authorities. Collected data was analyzed by using SPSS 17.0 and was considered statistically significant at p-value ? 0.05. The adjusted Odds Ratios (OR) and 95% confidence Interval (CI) was also estimated.Results: The risk of developing breast cancer differed significantly by ABO blood type in each of the two cohorts (p = 0.97) and this association between blood group and breast cancer risk was highly similar between the two independent populations. The adjusted risks of breast cancer associated with blood groups A, B, and AB were insignificant with risk factors for the disease. The association between ABO blood group and the subsequent risk of breast cancer was not modified to a statistically significant extent by age, BMI, age at menarche, menopausal status, marital status and smoking status.Conclusion: The association between blood group and breast cancer risk was insignificant and is still controversial. Further studies are necessary to identify the mechanisms by which ABO blood type may influence the risk of breast cancer.