Susceptibility to breast cancer is caused by a combination of genetic and environmental factors. Research is exploring which factors influence breast cancer risk, and by which mechanisms they exert their influence. Women should be informed about lifestyle factors influencing their life time breast cancer risk and encouraged by their physician to adapt changes in diet, physical activity, reproductive issues and use of hormone substitution after menopause, to minimize the risk. Patients identified as high risk to develop breast cancer can consider prophylactic surgery, chemo-preventive therapies and take part in personalized screening programs.