In this paper I employ a dynamic general equilibrium model to study macroe-conomic e®ects and welfare implications of alternative reforms to the U.S. health insurance system. In particular, I focus on expanding Medicare to the entire population, extending Medicaid, and having an individual mandate as well as other related medical reforms. All these reforms can be ¯nanced in several ways. I consider a stochastic OLG framework with heterogeneous agents facing uncertain health shocks. Individuals make optimal decisions on labor supply, health insurance, and medical services. As the amount of optimal medical consumption and hours worked are endogenous, this environment captures general equilibrium
effects. The model is calibrated to the U.S. data. Numerical simulations indicate that reforming the health insurance system has several important macroeconomic
effects on health expenditures, hours worked, and welfare.