The Centers for Medicare & Medicaid Services (CMS) administers Medicare, the nation’s largest health insurance program, which covers nearly 40 million Americans.

Medicare is a health insurance program for people age 65 or older, some disabled people under age 65, and people of all ages with End-Stage Renal Disease (permanent kidney failure treated with dialysis or a transplant).

Medicare has two parts: Part A (hospital insurance) and most people don’t have to pay for Part A; and Part B (medical insurance) with most people paying for Part B.

The Medicare Web site provides in depth information about Medicare, how to qualify, how to enroll, frequently asked questions, as well as the “Medicare Eligibility Tool” that gives you information about your eligibility and enrollment by asking a series of questions that are kept confidential.

Social Security will make the final decision on your eligibility and enrollment status.

If you are not a U.S. citizen or a lawfully admitted alien who has lived in the US continuously for a five-year period, you are asked to contact Social Security at (800) 772-1213 for your Medicare enrollment and eligibility.

The “Resources” section of the Web site offers contact information and tools to learn about your health care benefits.

Resources include:

A calculator for Medicare eligibility and enrollment date;

A calculator to provide you with an estimate of your Part B late enrollment penalty based on the 2010 premium amounts;

Social Security information for ordering a replacement Medicare card, changing your address or phone number; and applying for Social Security benefits, at

Other resource information includes: Railroad Retirement Board, toll-free at (877) 772-5772, or

As a registered user of the Medicare Web site, you will have access to personalized information regarding your Medicare benefits and services at

A comparison tool, Medicare Options Compare, helps you narrow your Medicare health plan choices and choose the plan that’s best for you.

“Your Medicare Coverage” is a tool that provides information about your health care benefits in Original Medicare (sometimes referred to as “fee for service.”

There are also Medicare publications to help you learn about Medicare eligibility and enrollment and that will guide you in choosing a plan that meets your needs, such as “Medicare and You 2010,” “Your Medicare Benefits,” and View More Basic Medicare Information Publications.” Information,