Medicare is the U.S. federal health-insurance program mainly serving people aged 65 and older.
President Lyndon B. Johnson signed Medicare into law in 1965 as part of the Great Society. The program initially focused on older Americans and was later expanded to cover certain younger people with qualifying disabilities and people with end-stage renal disease or amyotrophic lateral sclerosis under federal rules.
Medicare has several parts. Part A primarily covers hospital insurance, Part B covers medical insurance, Part C refers to Medicare Advantage plans offered by private insurers, and Part D helps cover prescription drugs. Beneficiaries can face premiums, deductibles, coinsurance, and network rules depending on the coverage they choose.
Medicare is different from Medicaid, which is a joint federal-state program based chiefly on income and other eligibility rules. The two programs can both cover some people, but they are separate systems with different funding and administration.