The House Budget Plan that would repeal the Affordable Care Act (ACA) and convert Medicaid to a block grant would trigger significant decreases in federal Medicaid spending and could result in substantial reductions in enrollment and payments to providers compared to current projections. The analysis finds that projected federal spending on Medicaid for the period 2013 to 2022 would fall by $1.7 trillion compared to current estimates, a 38 percent decline. Of that total, $932 billion in spending reductions would come from the repeal of the federal support for the ACA Medicaid expansion and another $810 billion would be due to federal Medicaid spending reductions that accompany the block grant. State-specific estimates are provided.