This report examines changes in joint eligibility and participation for the Supplemental Nutrition Assistance Program and Medicaid/CHIP between 2011 and 2015, when more than half of states expanded Medicaid to cover families earning up to 138 percent of the federal poverty level. In expansion states, the proportions of adults jointly eligible and only eligible for Medicaid increased between 2013 and 2015. In the three states examined with joint participation, rates increased for children and adults in South Carolina, were mixed in Illinois, and were stable in Idaho between 2013 and 2015.