Cardiovascular disease (CVD) is a leading cause of mortality among U.S. adults, especially low-income and uninsured adults. Non-Hispanic Black adults, who are overrepresented among low-income and uninsured populations, are disproportionately burdened by CVD mortality compared with non-Hispanic White adults. Medicaid expansion is associated with improved insurance coverage and access to care among low-income adults as well as reduced CVD mortality. It is unclear whether Medicaid expansion has reduced the Black-White disparity in CVD mortality. This study estimated a difference-in-differences model to compare changes in county-level CVD mortality ratios between expansion and non-expansion states. Findings indicate that Medicaid expansion is not associated with a statistically significant reduction in Black-White disparities in CVD mortality (β = -.039; p =.30). In conclusion, Medicaid expansion may be associated with improved health outcomes and access to care overall; however, it is insufficient to overcome other (i.e., social and economic) drivers of racial/ethnic disparities in CVD mortality.