Early detection of breast cancer through the use of mammography reduces long-term mortality from this disease, yet relatively little is known about its acceptance by the medical community. As part of a state health department cancer control program planning effort, we contacted 1,004 primary-care physicians in Pennsylvania to ascertain current breast cancer early detection practices. While 92% of the 557 eligible respondents reported conducting breast physical examinations at least annually in asymptomatic women age 50 or older, annual mammograms for this age group were ordered by only 42% of physicians. Obstetrician-gynecologists, as well as female and younger physicians, were more likely to obtain nondiagnostic mammograms regularly. Factors reported by physicians as affecting their practice of obtaining mammograms varied by patient age and, among patients 50 years and older, included the claim that their mammography practices represented optimal care (57% of the physicians), how often the patient visited their office (23%), patient refusal (16%), and cost of the examination (16%). Fear of radiation and expense were cited as the primary reasons for patient refusal. Public and physician education, as well as third-party payment changes, was viewed by the physicians as the most effective means to increase the level of breast cancer early detection in their geographic areas. This survey shows that the use of nondiagnostic mammography is still less than optimal, and identifies impediments to screening that need to be addressed in cancer control planning efforts.