Racial and ethnic differentials in uninsurance rates could be greatly reduced under the Affordable Care Act, potentially cutting the black-white differential by more than half and the Hispanic-white differential by just under one-quarter. Improving coverage for these populations will depend on states adopting policies that promote high enrollment in Medicaid/CHIP and new insurance exchanges. Coverage gains among Hispanics will depend on policies in California and Texas (where almost half of Hispanics live). If the projected coverage gains are realized, long-standing racial and ethnic differentials in access to care and health status could shrink considerably. This research was funded in part by the Annie E. Casey Foundation.