Millions of uninsured people use health care services every year. We estimated providers' uncompensated care costs in 2013 to be between $74.9 billion and $84.9 billion. In the aggregate, at least 65 percent of providers' uncompensated care costs were offset by government payments designed to cover the costs. Medicaid and Medicare were the largest sources of such government payments, providing $13.5 billion and $8.0 billion, respectively. Anticipating fewer uninsured people and lower levels of uncompensated care, the Affordable Care Act reduces certain Medicare and Medicaid payments. Such cuts in government funding of uncompensated care could pose challenges to some providers, particularly in states that have not adopted the Medicaid expansion or where implementation of health care reform is proceeding slowly.