Understanding Eligibility

Doctor looking over chart with woman

Unsure if you’re eligible for Medicare? Let us help you figure out where you stand.

Medicare Eligibility

You are generally entitled to Medicare if you meet any of the following criteria:

  • You are aged 65 or above.
  • You are disabled and have received disability benefits from Social Security or Railroad Retirement Board (RRB) benefits.
  • You have been diagnosed with end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS, “Lou Gehrig’s disease”).

Find the Best Medicare Plan for You

For more than 90 years, Blue Cross and Blue Shield companies have been putting members first, which is why most doctors trust us for Medicare coverage. Explore what Blue Cross and Blue Shield companies have to offer by entering your ZIP Code to find Medicare coverage that fits your needs.

  • If you receive insurance through an employer, please enter the ZIP Code. If you need further help identifying your BCBS company, please contact the employer who provides your insurance for assistance.
  • If you do not receive your insurance though an employer, please enter the ZIP Code for where you live.

Some employers offer BCBS Medicare coverage to their eligible retirees. To find out if you are eligible, reach out to your company benefits representative.

Select BCBS Provider

Federal employees, retirees and their families are insured by the Federal Employees Program (FEP).

Enrolling in Medicare

When to Enroll

You can enroll in Medicare Part A and Part B starting three months before you turn 65 or when you first qualify based on an eligible disability. This Initial Enrollment Period lasts seven months from that date.

Initial Enrollment Period

Your Initial Enrollment Period is when you first become eligible for Medicare. This is a seven-month window when you can enroll in Original Medicare (Part A and/or Part B). Or, you can choose a Medicare Advantage plan through a private insurer like Blue Cross and Blue Shield (BCBS) that covers all Parts A and B services and typically includes Medicare Prescription Drug (Part D) coverage.

You can also enroll in a BCBS Medigap (Medicare Supplement) plan if you are already enrolled in Original Medicare.

Once your Initial Enrollment Period has ended, you can only make enrollment changes during either the Medicare Open Enrollment Period or General Enrollment Period, unless you qualify for a Special Enrollment Period.

Individuals Aged 65 or Older

Initial Enrollment Period - 7 months

Your Initial Enrollment Period is based on the month in which you turn 65. It begins three months before your birth month, includes your birth month and extends until three months after your birth month.

Individuals Aged Under 65 with an Eligible Disability

Your Initial Enrollment Period is based on when you began receiving Social Security or Railroad Retirement Board (RRB) disability benefits. It begins the 22nd month after you began receiving benefits and continues until the 28th month after you began receiving benefits.

General Enrollment Period: January 1 through March 31

The General Enrollment Period offers an opportunity to enroll in Medicare Parts A and B. If you enroll in Medicare during the General Enrollment Period, your coverage starts July 1.

During the General Enrollment Period, you can:

  • Sign up for Original Medicare if you weren’t automatically enrolled and missed your Initial Enrollment Period.
  • Enroll in Part B if you had opted out of automatic enrollment, didn’t enroll or dropped your coverage.
  • If you enroll in Part B after your Initial Enrollment Period, you will pay a penalty, added to your monthly Part B premium.
  • If you already receive Social Security or certain retirement benefits, you may be automatically enrolled in Original Medicare during this period. Otherwise, you will need to sign up manually through the U.S. Social Security Administration.

Note: If you live in Puerto Rico and receive Social Security benefits, you will automatically be enrolled in Part A. However, you will need to apply for enrollment in Part B.

Medicare Annual Enrollment Period: October 15 through December 7

The Medicare Open Enrollment Period provides an annual opportunity to review and, if necessary, make enrollment changes to your Medicare coverage. During Open Enrollment, some examples of changes that you can make include:

  • Joining a Medicare Advantage (Part C) plan.
  • Changing from one Medicare Advantage plan to another.
  • Changing your Prescription Drug Coverage (Part D) plan if you are in Original Medicare.
  • Discontinuing your Medicare Advantage coverage and return to Original Medicare.

Download the Medicare Advantage (Part C) and Prescription Drug Plans (Part D) guide to find the coverage options offered by your local Blue Cross and Blue Shield (BCBS) company.

Special Enrollment Periods

There are certain situations when you can enroll in the Medicare program or other Medicare options, outside of the Initial or annual Open Enrollment Periods. For example, if you have health coverage through your employer that is terminated, you may be eligible for a Special Enrollment Period when you can enroll in Part B, as well as other Medicare options, such as Medicare Advantage.

More information about Special Enrollment Periods is available on the federal Social Security website.

Additional Enrollment Details

Medicare Advantage (Part C)

You must first enroll in Medicare Part A and Part B before joining a Medicare Advantage plan. Reach out to your local BCBS company for help choosing a Medicare Advantage plan and getting enrolled.


Prescription Drug Coverage (Part D)

You must be entitled to Part A or enrolled in Part B, and you must live in the designated geography of the plan you want to enroll in before joining a Medicare Part D plan. If you elect to receive Part D coverage after your Initial Enrollment Period window closes, a late enrollment penalty may be added to your premium.


Medigap (Medicare Supplement)

The open enrollment period for a Medigap policy is the six-month period that starts the first day of the month that you turn 65 or older and enrolled in Part B. After this period, your ability to buy a Medigap policy may be limited, and it may be more costly. Each state handles this differently, but there are additional open enrollment periods in some cases.

Note: Once you are enrolled in a Medigap (Medicare Supplement) plan, it renews every year as long as you pay your premium and the plan is available.


Medicare Part A and B (Original Medicare)

You will be automatically enrolled in Medicare Part A and Part B if you reach age 65 and receive Social Security or Railroad Retirement Board (RRB) retirement benefits. You will also be automatically enrolled if you are under age 65 with an eligible disability.

You will receive a Medicare card in the mail three months before your 65th birthday or your 25th month of disability. It will include instructions for opting out of enrollment for Part B, should you wish to do so.

You can apply for Medicare Part A and Part B under certain conditions:

  • You are eligible for Social Security or Railroad Retirement Board (RRB) benefits, but don’t receive them.
  • You qualify for Medicare due to End-Stage Renal Disease (ESRD).
  • You don’t qualify for premium-free Part A coverage.

Note: If you live in Puerto Rico and receive Social Security benefits, you will automatically be enrolled in Part A. However, you will need to apply for enrollment in Part B.

Find the Best Medicare Plan for You

For more than 90 years, Blue Cross and Blue Shield companies have been putting members first, which is why most doctors trust us for Medicare coverage. Explore what Blue Cross and Blue Shield companies have to offer by entering your ZIP Code to find Medicare coverage that fits your needs.

  • If you receive insurance through an employer, please enter the ZIP Code. If you need further help identifying your BCBS company, please contact the employer who provides your insurance for assistance.
  • If you do not receive your insurance though an employer, please enter the ZIP Code for where you live.

Some employers offer BCBS Medicare coverage to their eligible retirees. To find out if you are eligible, reach out to your company benefits representative.

Select BCBS Provider

Federal employees, retirees and their families are insured by the Federal Employees Program (FEP).

Medicare overview information on this website was developed by the Blue Cross and Blue Shield Association to help consumers understand certain aspects about Medicare. Viewing this Medicare overview does not require you to enroll in any Blue Cross Blue Shield plans. Plans are insured and offered through separate Blue Cross and Blue Shield companies. Medicare Advantage and Prescription Drug Plans are offered by a Medicare Advantage organization and/or Part D plan sponsor with a Medicare contract. Enrollment in these plans depends on the plan’s contract renewal with Medicare. To find out about premiums and terms for these and other insurance options, how to apply for coverage, and for much more information, reach out to your local BCBS company. Each Blue Cross and Blue Shield company is responsible for the information it provides. For more information about Medicare, including a complete list of plans available in your area, please contact the Medicare program at 1.800.MEDICARE (TTY users should call 1.877.486.2048) or visit www.medicare.gov.

Medicare has neither reviewed nor endorsed this information.