Why Do I Have 2 Different Medicare Numbers?

If you are enrolled in Medicare, you may notice that you have been issued 2 different Medicare cards with 2 different Medicare numbers. This can understandably cause confusion, as most people expect to only have one Medicare number.

In fact, there are certain situations where it is perfectly normal for a Medicare beneficiary to have 2 different Medicare numbers and cards at the same time.

Below we will explain:

  • What your Medicare number is
  • Why you may have 2 Medicare numbers
  • When you would use each Medicare number
  • How to avoid mistakes when using your cards

Understanding why you have 2 Medicare numbers and when to use each one will ensure you don’t face any issues getting reimbursed for medical care.

What Is a Medicare Number?

First, let’s review what a Medicare number actually is.

When you enroll in Medicare, you are issued a red, white, and blue Medicare card. Printed on the card is your Medicare number, which is also called your Medicare claim number.

This Medicare number consists of 11 characters:

  • The first 9 characters are numbers that match your (or your spouse’s) Social Security Number
  • The 10th character is a letter providing Medicare eligibility information
  • The 11th character is a number for benefits verification

Your Medicare number is unique to you. It is used for things like:

  • Processing Medicare claims
  • Verifying your eligibility
  • Billing your medical providers

You will need to present your Medicare card and number any time you receive medical services, fill a prescription, or access healthcare benefits.

Now that you understand what a Medicare number is, let’s look at why you may have 2 of them.

Why Do I Have 2 Medicare Numbers?

There are a few scenarios where a Medicare beneficiary can end up with 2 Medicare numbers and cards:

1. You qualified for Medicare before Social Security

If you qualified for Medicare prior to being eligible for Social Security benefits, you will initially receive a Medicare card with your own Social Security Number and a special code after it.

Here’s an example:


The “T” indicates you have Medicare Part A coverage only based on your work history, but are not receiving Social Security retirement benefits yet.

Once you sign up for Social Security, you will be issued a new Medicare card with your own Social Security Number and a different code:


The “A” means you have Medicare Part A and are actively receiving Social Security benefits.

So in this case, becoming eligible for Social Security triggered the issuance of your second Medicare card.

2. You qualify for Medicare through your spouse

Another common scenario is when you qualify for Medicare benefits based on your spouse’s work history and Social Security record.

For example, let’s say your spouse’s Social Security Number is 987-65-4321. When you become eligible for Medicare under their record, your first Medicare card would be:


The “B” indicates you have Medicare Part A coverage based on your spouse’s Social Security benefits.

Later on, when you enroll in Medicare Part B, you will be issued a second card showing:


This means you have Part A and Part B based on your spouse’s Social Security.

The new card is triggered when you enroll in Part B under your spouse’s benefits.

3. You enroll in a Medicare Advantage Plan

Finally, some people end up with 2 Medicare numbers if they switch between Original Medicare and Medicare Advantage Plans.

For example:

  • You originally had Original Medicare and received a card with your own Medicare number
  • You enrolled in a Medicare Advantage Plan and got a new membership card from the private insurer
  • If you later switch back to Original Medicare, you will be issued a new Medicare card with a different Medicare number than your original one

So moving in and out of Medicare Advantage can result in having different Medicare numbers over time.

As you can see, there are a few situations where you can legitimately end up with more than one Medicare number. Now let’s look at when to use each card.

When Should I Use Each Medicare Card?

If you have 2 valid Medicare cards, it’s crucial that you only use the correct card when receiving medical care and filing claims.

Here are some tips on when to use each Medicare number:

  • Only use the most recent Medicare card – This reflects your current Medicare enrollment. Destroy any old Medicare cards so you don’t use them by mistake.

  • If you have Original Medicare – Only use the card with your own Social Security Number on it. Do not use a card with your spouse’s Social Security Number for your claims.

  • If you have Medicare through your spouse – Only use the card reflecting your spouse’s Social Security Number and your current Medicare enrollment.

  • If you switch between Original Medicare and Medicare Advantage – Carefully check which card matches the coverage you currently have in place.

  • When in doubt, check with Medicare – You can call 1-800-MEDICARE to verify which Medicare number is valid for submitting claims.

  • Update providers when you switch cards – Let your healthcare providers know anytime you transition to a new Medicare card so they bill correctly.

By closely following these guidelines, you can avoid any reimbursement issues stemming from having 2 different Medicare numbers.

Always notify healthcare providers right away if you receive a new Medicare card. And shred old Medicare cards to avoid confusion.

Why Using the Wrong Card Matters

You might be wondering why it matters so much whether you use the correct Medicare card and number.

The main reason is that using the wrong Medicare number can lead to denied claims, delayed payments, and headaches getting your medical bills covered.

Here are some of the problems you can encounter if you present the incorrect Medicare card:

  • Claims processing issues – Medicare will not be able to verify eligibility if you use an outdated number, resulting in denied or stalled claims.

  • Incorrect coordination of benefits – If you have 2 numbers but only give one to providers, it can impact how primary/secondary insurance is determined.

  • Problems verifying enrollment – Providers will not be able to confirm your active Medicare coverage if you show a card with an old, invalid number.

  • Enrollment errors – In some cases, giving the wrong Medicare number can lead to your enrollment records being incorrect.

  • Reimbursement delays – It often takes significant time and effort to resolve reimbursement problems due to providing the inaccurate Medicare ID.

To avoid any of these headaches, always be diligent about using the Medicare card that aligns with your current Medicare enrollment.

Take time to explain to providers why you have 2 cards and which one is valid. This will help prevent administrative mix-ups.

Tips for Managing 2 Medicare Numbers

If you find yourself in the position of having 2 Medicare identification cards, here are some tips:

  • Carefully review both cards and understand when each is applicable. Ask Medicare if you are uncertain.

  • Label each card with the coverage terms, such as “Original Medicare” or “Under Spouse”.

  • Destroy old Medicare cards so they aren’t used accidentally.

  • Notify your healthcare providers when your primary Medicare card changes.

  • Make sure billing departments have your current and correct Medicare ID.

  • If claims are denied, double check that the provider used the right Medicare number.

  • Request an updated insurance card from any supplemental coverage when your Medicare number changes.

  • Update your Medicare number in electronic health records so it matches your current card.

  • Carry the correct card to appointments and imaging/labs to prevent issues upfront.

Following these simple steps can help prevent frustration and ensure your medical claims are billed smoothly when you have 2 different Medicare cards.

When Will I Get a New Medicare Number?

In most cases, you will be issued a new Medicare number when a material change occurs in your Medicare enrollment or eligibility.

Some examples include:

  • Starting to receive Social Security retirement benefits
  • Enrolling in Medicare Part B after already having Part A
  • Qualifying for Medicare based on age rather than disability
  • Moving from Original Medicare to Medicare Advantage (or vice versa)
  • Changing your name or gender with the Social Security Administration

New Medicare numbers are generated automatically by the Medicare system in these situations to reflect your updated enrollment status.

If none of these changes occur, you should generally keep the same Medicare number for life.

You typically will not be assigned a brand new Medicare number out of the blue. Some action must trigger a new enrollment record to generate a new card.

Steps If You Lost Your Medicare Card

What if you simply lose your Medicare card and can’t find the correct number? Don’t worry, you can take steps to find it:

  • Check your old tax records which may show Medicare ID numbers.
  • Contact your Medicare Advantage Plan if enrolled in one.
  • Use your Social Security statements to identify numbers.
  • Call Medicare at 1-800-MEDICARE to find your number.

Medicare Card Full Explanation Everything You Need to Know


Are there 2 Medicare cards?

The front of your Medicare card indicates whether you are enrolled in Part A and/or Part B under the heading “IS ENTITLED TO.” If you are enrolled in the Medicare Part C (Medicare Advantage) plan or Medicare Part D (prescription drug) plan, that information appears on a separate card and not on your Medicare card.

Why is my Medicare number different?

Your card has a Medicare number that’s unique to you — it’s not your Social Security Number. This helps protect your identity. The card shows: You have Medicare Part A (listed as HOSPITAL), Part B (listed as MEDICAL), or both.

Can I have 2 Medicare numbers?

Keep in mind, you can only be on 2 different Medicare cards at the same time. If you choose to leave a card and you’re the contact person, we’ll assign a new contact person for the card.

Why did I get a new Medicare number 2023?

In response to a recent data breach, the Centers for Medicare & Medicaid Services (CMS) is mailing approximately 47,000 Medicare cards with new Medicare Beneficiary Identifier (MBI) numbers to those affected.

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