This paper addresses three questions to assess the fiscal challenges Medi-Cal may pose in the future for California policymakers: First, how much are Medi-Cal costs likely to grow over the next decade in the absence of policy changes? Second, how will this growth compare to revenue growth? And third, what factors are driving Medi-Cal costs? To answer these questions this paper forecasts the expected costs of the Medi-Cal program through 2015, as well as examines the forces underlying recent growth in Medi-Cal expenditures.