What is Medicare?

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Medicare is our country’s federal health insurance program for people age 65 or older. People younger than age 65 with certain disabilities, permanent kidney failure, or amyotrophic lateral sclerosis (Lou Gehrig’s disease), can also qualify for Medicare. The program helps with the cost of health care, but it doesn’t cover all medical expenses or the cost of most long-term care. You have choices for how you get Medicare coverage. If you choose to have Original Medicare (Part A and Part B) coverage, you can buy a Medicare Supplement Insurance (Medigap) policy from a private insurance company. Medigap covers some of the costs that Medicare does not, such as copayments, coinsurance, and deductibles. If you choose Medicare Advantage, you can buy a Medicare-approved plan from a private company that bundles your Part A, Part B, and usually prescription drug coverage (Part D) into one plan. 

Although the Centers for Medicare & Medicaid Services (CMS) is the agency in charge of the Medicare program, Social Security processes your application for Original Medicare (Part A and Part B).

Parts of Medicare.

Social Security enrolls you in Original Medicare (Part A and Part B). 

  • Medicare Part A (hospital insurance) helps cover inpatient care in hospitals (including critical access hospitals) and skilled nursing facilities (not custodial or long-term care). Part A also pays for some home health care and hospice care and inpatient care in a religious non-medical health care institution.
  • Medicare Part B (medical insurance) helps cover medically necessary doctors’ services, outpatient care, home health services, durable medical equipment, mental health services, and other medical services. Part B also covers many preventative services. Other parts of Medicare are run by private insurance companies that follow rules set by Medicare.
  • Supplemental (Medigap) policies help pay Medicare out-of-pocket copayments, coinsurance, and deductible expenses. 
  • Medicare Advantage Plan (previously known as Part C) includes all benefits and services covered under Part A and Part B, plus prescription drugs and additional benefits such as vision, hearing, and dental, bundled together in one plan. 
  • Medicare Part D (Medicare prescription drug coverage) helps cover the cost of prescription drugs.

Medicare Part A (hospital insurance)

People age 65 or older, who are citizens or permanent residents of the United States, are eligible for Medicare Part A. You’re eligible for Part A at no cost at age 65 if one of the following applies: 

  • You receive or are eligible to receive benefits from Social Security or the Railroad Retirement Board (RRB). 
  • Your spouse (living or deceased, including divorced spouses) receives or is eligible to receive Social Security or RRB benefits. 
  • You or your spouse worked long enough in a government job through which you paid Medicare taxes.
  • You are the dependent parent of a fully insured deceased child. 

If you don’t meet these requirements, you may be able to get Medicare Part A by paying a monthly premium. Usually, you can purchase this coverage only during designated enrollment periods.

NOTE: Even though the full retirement age for Social Security is no longer 65, you should sign up for Medicare three months before your 65th birthday. You can apply at www.ssa.gov

Before age 65, you are eligible for Medicare Part A at no cost if one of the following applies:

  • You’ve been entitled to Social Security Disability Insurance (SSDI) benefits for 24 months. 
  • You receive a disability pension from the RRB and meet certain conditions. 
  • You receive SSDI benefits because you have Lou Gehrig’s disease (amyotrophic lateral sclerosis). 
  • You worked long enough in a government job through which you paid Medicare taxes and have met the requirements of the SSDI program for 24 months. 
  • You’re the child or widow(er) age 50 or older, including a divorced widow(er), of a worker who has worked long enough under Social Security or in a Medicare-covered government job, and you meet the requirements of the SSDI program. 
  • You have permanent kidney failure (end-stage renal disease) and you receive maintenance dialysis or a kidney transplant and one of the following applies: 

—You’re eligible for or receive monthly benefits under Social Security or the railroad retirement system.

—You’ve worked long enough in a Medicare-covered government job. 

—You’re the child or spouse (including a divorced spouse) of a worker (living or deceased) who has worked long enough under Social Security or in a Medicare-covered government job.

Medicare Part B (medical insurance)

Anyone who’s eligible for Medicare Part A at no cost can enroll in Medicare Part B by paying a monthly premium. Some people with higher incomes will pay a higher monthly Part B premium. For more 5 information, visit our webpage 

Medicare Premiums: Rules for Higher Income Beneficiaries or visit www.ssa.gov/benefits/medicare/mediinfo.html 

If you’re not eligible for Part A at no cost, you can buy Part B without having to buy Part A. You must be age 65 or older and one of the following: 

  • A U.S. citizen. 
  • A lawfully admitted noncitizen who has lived in the United States for at least five years.

You can only sign up for Part B during designated enrollment periods. If you don’t enroll in Part B when you’re first eligible for it, you may have to pay a late enrollment penalty for as long as you have Part B coverage.