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