BACKGROUND There is currently an epidemic of breast cancer in women 65 years of age and older. The purposes of this paper are to explore the breast cancer screening behaviors of older women and to identify some of the determinants of screening in these women. METHODS Data were analyzed from the 1987 National Health Interview Survey, a continuous nationwide household interview survey of the U.S. civilian, noninstitutionalized population. RESULTS As in other studies, the utilization of breast cancer screening by older women was less in older women than in younger women. This was true for both mammography and clinical breast examination. A number of determinants of screening in older women were identified here. Women with a usual source of care and/or no activity limitation, as well as high school graduates, were the ones most likely to have received a screening mammogram and/or a screening clinical breast exam during the past year. CONCLUSIONS The failure of older women to receive adequate breast cancer screening is an important concern which should be reevaluated, given the breast cancer epidemic in this population. This study identified a number of determinants of breast cancer screening in older women. For the most part, these determinants point to the primary care physician as the key to breast cancer screening in these women. Therefore, the primary care physician must be informed of, and encouraged to follow, the recommendations for periodic breast cancer screening in older women.