Medicare is a social insurance program administered by the United States government, providing health insurance coverage to people who are aged 65 and over, or who meet other special criteria. The medicare program also funds residency training programs for the vast majority of physicians in the United States. Medicare operates as a single-payer health care system.^[1] The Social Security Act of 1965 was passed by Congress in late-spring of 1965 and signed into law on July 30, 1965, by President Lyndon B. Johnson as amendments to Social Security legislation. At the bill-signing ceremony President Johnson enrolled former President Harry S. Truman as the first Medicare beneficiary and presented him with the first Medicare card.

http://en.wikipedia.org/wiki/Medicare_%28United_States%29