The U.S. health care system is a pluralistic, market-based approach that incorporates various public and private payers and providers. Passage of Medicare and Medicaid, combined with rapid advances in technology and an aging population, has contributed to rising health care costs that typically increase faster than general inflation. This entry will review health care financing, exploring where the money is spent, who pays for health care, what the reimbursement mechanisms for providers are, and some issues central to the discussion of reform of health care financing. To effectively advocate health care reform, social workers must understand health care financing.