Although the major part of the burden of disease for female breast cancer occurs at older age, less is known about the development and progression in this age group than in women under 60 years of age. As the world population continues to age, the percentage of elderly is increasing in all communities and the incidence of breast cancer will rise accordingly. Improving detection and diagnosis, and a better understanding of the mechanisms that play a role in this age group, will not only improve quality of life in older sufferers but could also contribute to the management of this disease in the adult population as well. Development of breast cancer in the older woman is influenced by many variables that may differ from the risk factors that are involved in younger women. In addition to well-described variables at younger ages such as family history, hormonal exposure, lifestyle factors and pre-existing benign breast disease, in older women age-related changes in breast tissue, biochemistry, inflammatory responses and the immune system, as well as accumulation of DNA damage and spontaneous mutations are suspected to contribute to the complex relationship between ageing and breast cancer. We review the available data on the role of age-related changes and genetic mutations in the development of breast cancer in older women as well as their effects on estrogen metabolism and free oxygen radical inactivation.