Understanding the health care spending and utilization of various types of Medicaid enrollees is important for assessing the budgetary implications of both expansion and contraction in Medicaid enrollment. Despite the intense debate surrounding the Affordable Care Act (ACA), however, little information is available on the spending and utilization patterns of the nonelderly adult enrollees who became newly eligible for Medicaid under the ACA. Using data for 2012–14 from the Medical Expenditure Panel Survey, we compared health care spending and utilization of newly eligible Medicaid enrollees with those of nondisabled adults who were previously eligible and enrolled. We found that average monthly expenditures for newly eligible enrollees were $180—21 percent less than the $228 average for previously eligible enrollees. Utilization differences between these groups likely contributed to this differential.