The discussion of breast cancer in the older woman implies an outline of unique aspects of cancer and aging. In this analysis, five aspects are highlighted because they pertain to breast cancer control: the diversity of the older population; the age-related increase in cancer susceptibility; the changes in tumor biology that occur with aging; and the implication of these factors for the prevention and treatment of cancer. The comprehensive geriatric assessment accounts for the diversity of the older population in terms of functional reserve and life expectancy and allows an individualized approach to the elderly. The increased susceptibility of the aged to environmental carcinogens has multiple causes and provides theoretical support to cancer prevention to the older individuals. The natural behavior of cancer may change with age due to intrinsic changes in the tumor cells as well as in the tumor host and may lead to both increased and decreased aggressiveness of the neoplasm. In the case of breast cancer, age seems associated with a more indolent tumor. Cancer screening seems effective in older patients with a life-expectancy of 5 or more years. Treatment of cancer with chemotherapy may be associated with increased risk of complications, especially mucositis and neutropenia. The latter may be ameliorated by prophylactic use of growth factors and correction of anemia.