Medicaid, the provider of health insurance coverage for about one in five Americans and the largest payer for long-term care services in the community and nursing homes, continues to be a key part of health policy debates at the federal and state level. Important Medicaid issues to watch in 2019 include Medicaid expansion developments amid ongoing litigation about the ACA’s constitutionality as well as Medicaid demonstration waiver activities, including those focused on work requirements and other eligibility restrictions. States are also likely to continue to pursue initiatives to address the opioid crisis, and the recent passage of bi-partisan legislation with new tools and financing could bolster these efforts. Primary areas of federal policy to watch in 2019 with implications for Medicaid include the expiration of temporary funding for Puerto Rico and the US Virgin Islands in the absence of legislative action as well as potential regulatory changes to public charge policies that would likely lead to Medicaid enrollment declines among immigrant families. Finally, reforms in benefits, payment and delivery systems continue to evolve as states and the federal government focus on managed care, social determinants of health, prescription drugs, and community based long-term care. While beyond the scope of this brief, Congress and states could also consider broader health reform that could expand the role of public programs in health care including Medicare for All or Medicaid buy-in programs that could have significant implications for Medicaid.