The optimal upper age limit in mammographic screening for breast cancer is still a matter for debate. The incidence of breast cancer rises gradually with increasing age and, without screening, breast cancer in elderly women is diagnosed at a more advanced stage than in younger women. After menopause, much of the glandular tissue of the breast is replaced by fat, which facilitates the mammographic detection of breast cancer in older women. Furthermore, the tumour growth rate decreases with increasing age. Recently, a reduction in breast cancer mortality due to mammographic screening has been shown for women aged up to 75 years. There is a lack of data for women over the age of 75 years, however, because the number of women screened in the only study that included this age category is too small to give reliable results. We conclude that mammographic screening is beneficial at least up to the age of 75 years, and may also be beneficial up to age 85 years in healthy women with a good life expectancy.