This paper addresses the question of whether Medicaid is in fact a high-cost program after adjusting for the health of the people it covers. We compare and simulate annual per capita medical spending for lower-income people (families with incomes under 200% of poverty) covered for a full year by either Medicaid or private insurance. We first show that low-income privately insured enrollees and Medicaid enrollees have very different socioeconomic and health characteristics. We then present simulated comparisons based on multivariate statistical models that estimate the effects of private and Medicaid coverage on the likelihood of using services, and the level of expenditures, given any use, holding constant demographic, economic, and health status characteristics. The simulations demonstrate that if people with Medicaid coverage--with their health status, disability, and chronic conditions--were given private coverage, they would cost considerably more than they do today. Conversely, if the privately insured were given Medicaid coverage, spending would be lower. We find no evidence that spending differences between Medicaid and private coverage for low-income people are due to lower service use by Medicaid beneficiaries. We conclude that most of the difference in expenditures is due to differences in provider payment rates.