Data from seven studies sponsored by the National Cancer Institute (NCI) were used to determine current rates of breast cancer screening and to identify the characteristics of and reasons for women not being screened. All seven studies were population-based surveys of women aged 50 to 74 years without breast cancer. While over 90% of non-Hispanic white respondents had regular sources of medical care, 46% to 76% had had a clinical breast examination within the previous year, and only 25% to 41% had had a mammogram. Less educated and poorer women had had fewer mammograms. The two most common reasons women gave for never having had a mammogram were that they did not know they needed it and that their physician had not recommended it. Many physicians may have overlooked the opportunity to recommend mammography for older women when performing a clinical breast examination and to educate their patients about the benefit of screening mammography.