There is a substantial heterogeneity of interests within the Medicaid program. Its major beneficiary groups include the elderly, people with disabilities, children in low-income families, and adults receiving Aid to Families with Dependent Children. Providers who deliver medical services to these recipients represent another set of potential claimants. These groups are likely to be treated differently by the politics that affect the design and management of the Medicaid program. The Medicaid recipient groups vary in several important dimensions: First, the groups differ politically, a dimension that includes their political participation, their relationships to parties and electoral coalitions, the images they present to other political actors, and the legacy of public policies that affect them. Second, the groups have different medical and social needs. Third, the groups differ with respect to economic constraints, including the political economy of labor markets and of government spending programs, and they have differing relationships to the various types of medical providers. The medical providers are themselves political actors with a variety of characteristics that create political advantages relative to recipients, although there is also diversity among providers. The politics of the Medicaid program involves more than simply technical decisions about eligibility, coverage of medical services, reimbursement, and the implementation of managed care initiatives. Instead the differences between the program’s multiple claimants are an important element of current Medicaid politics and the likely path of future reforms.