Medicare, the nation's largest health insurance program, covers nearly 55 million Americans. It is a health insurance program for people 65 years of age and older, some disabled people under 65 years of age, and people with End-Stage Renal Disease (permanent kidney failure treated with dialysis or a transplant).

Medicare consists of two programs: Part A (Hospital Insurance) and Part B (Supplemental Medical Insurance). Most people do not have to pay for coverage under Part A; Part B coverage is paid for by a monthly premium.

Part A (Hospital Insurance) helps pay for: inpatient hospital care; critical access hospitals (small facilities that give limited outpatient and inpatient services to people in rural areas); skilled nursing facilities; hospice care; and some home health care.

Most people get Part A automatically when they turn age 65. They do not have to pay a monthly premium for Part A because they, or a spouse, paid Medicare taxes while they were working.

If you (or your spouse) did not pay Medicare taxes while you worked and you are age 65 or older, you still may be able to buy Part A. You can call the Social Security Administration toll free at 1-800-772-1213 or call your local Social Security office for more information about buying Part A. If you get benefits from the Railroad Retirement Board, call your local RRB office or 1-800-808-0772.

Part B (Medical Insurance) helps pay for: physicians' and surgeons' services; outpatient hospital care (such as an emergency room or same-day surgery clinic); some home health care not covered by Part A; laboratory tests, x-rays and other diagnostic services; most physical and occupational therapy and speech pathology services; radiation therapy, kidney dialysis, and certain organ transplants; some durable medical equipment; and certain drugs.

In 2016, the Medicare Part B premium ranges from $121.80 - 389.80 per month, depending upon your income. In some cases this amount may be higher if you did not choose Part B when you first became eligible at age 65. The cost of Part B may go up 10% for each 12-month period that you could have had Part B but did not sign up for it, except in special cases. You will have to pay this extra 10% for the rest of your life.

Enrolling in part B is your choice. You can sign up for Part B anytime during a 7 month period that begins 3 months before you turn 65. Visit your local Social Security office, or call the Social Security Administration at 1-800-772-1213 to sign up. If you choose to have Part B, the premium is usually taken out of your monthly Social Security, Railroad Retirement, or Civil Service Retirement payment. If you do not get any of the above payments, Medicare sends you a bill for your part B premium every 3 months.

Eligibility: Individuals are generally eligible for Medicare if they or their spouse worked for at least 10 years in Medicare-covered employment, and they are 65 years old and a citizen or permanent resident of the United States. A person might also qualify for coverage if they are a younger person with a disability or with End-Stage Renal Disease (permanent kidney failure requiring dialysis or transplant).

If you have questions about your eligibility for Medicare Part A or Part B, or if you want to apply for Medicare, call the Social Security Administration. The toll-free telephone number is: 1-800-772-1213. The TTY-TDD number for the hearing and speech impaired is 1-800-325-0778.

You can also find information on Medicare in an AARP report, Meet Medicare (.pdf).