When the Affordable Care Act of 2010 is fully implemented, it will extend health insurance coverage to many adult Americans who currently lack it. It is not known, however, how the health reform legislation will affect children and parents who would otherwise be uninsured. Based on our analysis, the Affordable Care Act has the potential to cut the number of uninsured children by about 40 percent, from 7.4 million to 4.2 million, and the number of uninsured parents by almost 50 percent, from 12.7 million to 6.6 million. However, the actual impact will depend on increasing the share of children and parents who are enrolled in public coverage and on other implementation outcomes. Most strikingly, if the requirement that states continue their Medicaid and Children's Health Insurance Program (CHIP) coverage is rescinded and if Congress does not continue funding CHIP, the uninsurance rate of children could more than double, increasing from 4.2 million to 7.9-9.1 million children. In that case, the uninsurance rate among children would be higher than if the Affordable Care Act had not been adopted.