Under welfare reform law, with certain exceptions, noncitizen immigrants who arrived in the United States after August 1996 were barred from Medicaid benefits, although they may still be covered for emergency services. Assessing the effects of this change has been problematic, because few data are available on the number and costs of immigrants on Medicaid. Analyses for this report were based on the Medicaid Quality Control database. The report provides national and state-by-state estimates of the number and cost of noncitizen Medicaid beneficiaries.