Disparities in US breast cancer mortality between older Black and White women have increased in the last 20 years. Regular mammography use is important for early detection and treatment: its utilization among older Blacks especially in counties with high Black mortality is of interest, but its extent and determinants are unknown. We used Medicare claims for Black and White women 65-74 years old in 203 counties with the highest Black breast cancer mortality. Outcomes over 6 years were as follows: ever mammogram, i.e., C 1 screening mammogram, and regular mammogram, i.e., C 3 mammograms. With logistic regressions, we examined the independent effect of race on screening controlling for individual- and county-level factors. Of 406,602 beneficiaries, 17 % were Black. Ever and regular mammogram was significantly lower among Blacks (51.6 vs. 56.9 %; 32.9 vs. 43.1 %, respectively). Controlling for covariates, including use of cervical cancer screening, flu shots, or lipids tests, Black women were more likely to have ever mammogram (OR 1.23, CI 1.20-1.25), but not regular mammogram (OR 0.95, CI 0.93-0.97) than White women. County-level managed care penetration was negatively associated with ever and regular mammograms. In Medicare enrollees from these counties, breast cancer screening was low. Black women had same or better odds of screening than White women. Some health care factors, e.g., managed care, were negatively associated with screening. Further studies on the determinants of mammography utilization in older women from these counties are warranted.