Breast-cancer risk factors, mammography history, and breast cancer detection rates were compared for women aged 50-64 years versus women 65 years and older. Mammographic screening examinations were performed on 936 women at least 65 years old and 1,926 women aged 50-64 years at a mobile van and an outpatient clinic of a tertiary referral university hospital. Breast- cancer risk factors and frequency and timing of previous mammograms were assessed on all women. Of the 2,862 women screened, 520 (18.2%) were black. Women aged 65 and older were significantly more likely to be nulliparous, and over 30 years old at first pregnancy than women aged 50-64 years. The proportion of women who reported ever having a mammogram did not differ by age. For women who reported a previous mammogram, the intervals of the previous screening did not differ significantly by age group. Cancer detection rates were higher among women aged 65 and over at both locations. Among age and race groupings, the highest cancer detection rate occurred in black women over 65 years (19.7/1,000). Cancer detection rates were high enough to suggest that screening elderly women is efficacious. Because elderly black women may be less aware of breast-cancer risk factors, relying on self-referral for screening this population may be inappropriate. Barriers to mammographic screening among elderly women warrant further study.