California has a lot to lose if the Affordable Care Act (ACA) is repealed. The state made significant investments in implementing the law successfully, and under the ACA cut the number of uninsured residents in half, from 6.5 million in 2013 to 3.3 million in 2015—the largest decline in the uninsured rate of any state.1 The two major reasons for this drop in uninsurance were the expansion of Medicaid and the provision of financial assistance for purchasing coverage through the state health insurance marketplace, Covered California. As a result of these policies, California experienced a significant reduction in health coverage disparities: the biggest drops in the uninsurance rate were among those least likely to have coverage before the ACA, namely those with the lowest income, young adults, part-time workers, and Latinos.2 Repealing the ACA threatens not only to leave millions without health insurance, but also to undo the progress California has made in reducing inequality of health insurance access. This brief focuses on Californians enrolled in expanded Medi-Cal (the state’s Medicaid program) and those who receive subsidized coverage through Covered California, the two groups most immediately affected if the ACA is repealed. However, many more Californians could see diminished health coverage under various Congressional Republicans’ proposals to repeal and replace the ACA.