Breast cancer is the most common cancer worldwide. Incidence and mortality have reached a plateau and appear to be dropping in both United States and parts of Western Europe. This decline has been attributed to several factors such as early detection through the use of screening mammography and appropriate use of systemic adjuvant therapy. Breast cancer is a disease and that is predominantly influenced by risk factors which can be allocated to one of four groups: first, family history / genetic which accounts for 15% of all breast cancer cases. The second group which is the most known risk factor for breast cancer can be linked to hazardous effects of hormonal exposures such as early age at menarche, late age at menopause, small number of children and nulliparity, late age at first birth and little or no breast feeding. Long term use of hormone replacement therapy but apparently not long term use of oral contraceptives is also important. The third group is high mammographic breast density which has been shown to be one of the most significant markers of breast cancer risk and the fourth group is having a history proliferative benign breast disease.