Background: Among women, breast cancer is the leading cause of death due to cancer worldwide. Aim: To describe the epidemiology of breast cancer mortality in Chilean women by age, time trend and explore its ecological association with socio-demographic variables. Material and methods: Descriptive study of age specific death rates (2009-2013), and time trend analysis of crude mortality rates (1995-2013) using RiskDiff analysis. Additionally, time trend analysis of age specific death rates was done using Jointpoint regression. The relationship between county mortality risk and socio-demographic variables in the period 2001-2008 was done through an ecological analysis. Socio-demographic variables were: education, income, occupation, housing and living in rural areas. Results: Breast cancer mortality in Chilean women increases with age, with a sharp increase from 80 years old on. In the 1995-2013 period the increase in the crude death rate was 21.8%, this increment was due to changes in demographic structure (43.4%) and decrease in risk (21.7%). The county relative risk of breast cancer mortality is positively associated with education level and negatively associated with living in rural areas. Conclusions: The risk of dying from breast cancer in women has decreased in the period 1995-2013. Nonetheless, the crude death rate has increased in the same period. At an ecological level (counties), breast cancer mortality in Chile is associated with a higher socioeconomic status, measured by educational level and living in rural areas.Background: Among women, breast cancer is the leading cause of death due to cancer worldwide. Aim: To describe the epidemiology of breast cancer mortality in Chilean women by age, time trend and explore its ecological association with socio-demographic variables. Material and methods: Descriptive study of age specific death rates (2009-2013), and time trend analysis of crude mortality rates (1995-2013) using RiskDiff analysis. Additionally, time trend analysis of age specific death rates was done using Jointpoint regression. The relationship between county mortality risk and socio-demographic variables in the period 2001-2008 was done through an ecological analysis. Socio-demographic variables were: education, income, occupation, housing and living in rural areas. Results: Breast cancer mortality in Chilean women increases with age, with a sharp increase from 80 years old on. In the 1995-2013 period the increase in the crude death rate was 21.8%, this increment was due to changes in demographic structure (43.4%) and decrease in risk (21.7%). The county relative risk of breast cancer mortality is positively associated with education level and negatively associated with living in rural areas. Conclusions: The risk of dying from breast cancer in women has decreased in the period 1995-2013. Nonetheless, the crude death rate has increased in the same period. At an ecological level (counties), breast cancer mortality in Chile is associated with a higher socioeconomic status, measured by educational level and living in rural areas.