This brief assesses Medicaid/Children’s Health Insurance Program (CHIP) participation rates and the number of uninsured children who are eligible for Medicaid or CHIP using the most recent data available from the American Community Survey. Since 2008, Medicaid/CHIP participation rates have risen by 5.5 percentage points among children, increasing to 87.2 percent in 2011; in that year, 20 states (including the District of Columbia) had participation rates at or above 90 percent and four states had rates below 80 percent. These findings suggest that the increased state and federal policy efforts aimed at reducing the number of eligible but uninsured children have been yielding results and that there is scope for more progress, by increasing participation in the lower-performing states. However, despite the potential for further progress, there is uncertainty about how children’s coverage will change in the coming years.