OBJECTIVE: In January 1991, Medicare extended its mammography benefit to reimburse for breast cancer screening mammograms. In 1991 and again in 1993, the National Cancer Institute Breast Cancer Screening Consortium (BCSC) conducted a survey to test the hypothesis that this benefit would increase mammography use among women over the age of 65. METHODS: The authors analyzed data on non-Hispanic white women ages 65 to 74 living in 11 geographic areas targeted by the BCSC for an earlier study--six that had received cancer screening educational interventions and five control subsites--to measure the impact of the newly adopted Medicare benefit on the use of mammography and use of Medicare to reimburse mammography costs. RESULTS: The data show little overall increase between 1991 and 1993 in reported mammography use among respondents to the survey. However, in six intervention and five control subsites there was an increase in the percentage of women who reported using public payment sources to at least partially reimburse the cost of mammograms. In three intervention subsites, the increase from 1991 to 1993 in the percentage of women using public sources of payment was greater than in the corresponding control subsites. CONCLUSIONS: These findings suggest that public health interventions are more likely to succeed when educational promotion accompanies a financial benefit.