Medicare, national health insurance program in the United States for persons aged 65 and over and the disabled. It was established in 1965 with passage of the Social Security Amendments and is now run by the Centers for Medicare and Medicaid Services. Coverage for certain people with disabilities began in 1973. Medicare provides for a basic program of hospital insurance, under which enrollees are protected against major costs of hospital and related care; and a supplementary medical insurance program, through which persons are aided in paying doctor bills and other health-care bills. It is funded by a tax on the earnings of employees that is matched by the employer and by premiums paid by enrollees. In 2012 some 51 million Americans were enrolled in Medicare. Legislation passed in 2003 provides for a drug benefit program (beginning in 2006), higher premiums for enrollees earning more than $80,000, and subsidies over 10 years to encourage private insurers to compete with Medicare.