This research brief from the Urban Institute Health Policy Center, funded by the Robert Wood Johnson Foundation, describes how millions of Americans will benefit from the expansions of health insurance coverage through the implementation of the Patient Protection and Affordable Care Act. In preparing this analysis, the Urban Institute used a simulation model to update estimates on how the various sections of the national health care reform legislation would impact Americans currently without health insurance coverage. The analysis finds that when the legislation is fully implemented, 43.8 million Americans would obtain health insurance coverage through state health insurance exchanges while an additional 13.1 million adults and 3.7 million children would obtain coverage through the expansion of Medicaid.