peer reviewed ; Breast cancer incidence in Belgium is on the top of European countries, with 9.697 new cases in 2008 and 106/100.000 women/year. The explanation of this high incidence in our country is probably the accumulation of risk factors (many of them are linked to lifestyle), and the impact of screening and registration of cases. The relative impact of each of theses factors is less clear because we don't have powerful statistical studies. Belgium is slightly above the European mean for breast cancer mortality, with 19,4/100.000 women/year and an all stages 15-year survival of 75%. Breast cancers are responsible for around 3% of all-cause mortality in Belgian women. This article discusses the causes of this high Belgian incidence and of current decrease of incidence in western countries, and reviews known and less known risk factors of breast cancers, with a special focus on menopause hormonal treatments.