Beginning in FY 2014, policy changes introduced by the Affordable Care Act (ACA) have been driving Medicaid enrollment and spending growth. This report provides an overview of Medicaid enrollment and spending growth with a focus on state Fiscal Year (FY) 2015 and state Fiscal Year 2016. Findings are based on interviews and data provided by state Medicaid directors as part of the 15th annual survey of Medicaid directors in all 50 states and the District of Columbia conducted by the Kaiser Commission on Medicaid and the Uninsured (KCMU) and Health Management Associates (HMA). Information collected in the survey on policy actions taken during FY 2015 and FY 2016 can be found in the companion report. Key findings related to Medicaid enrollment and spending growth are described below.