This paper reports the results of a practice-based intervention program to increase mammography screening among women 65 and older who receive their health care in the private sector. Forty-three primary-care practices and 2147 women in central and western North Carolina were enrolled in the study, and 1911 women completed all phases of the study. The intervention was a three-stage educational and counseling program designed to become progressively more intensive at each stage. The interventions included provider education in the form of current information on issues in mammography for older women, simply written educational materials on breast cancer and screening mailed to women, and a brief telephone counseling session for the women. While the analysis revealed no overall effect across all three stages of the intervention program, tests for interaction indicated a significant program effect for women who were 80 or older, had less than 9 years of education, were black, or had no private insurance to supplement Medicare. The results suggested that providing primary-care physicians with information on screening older women and providing the women with useful educational materials can increase participation in screening mammography among subgroups of women currently least likely to receive mammography screening.