Are Medicare and Social Security Numbers the Same?

Medicare and Social Security are two major federal government programs that provide benefits to millions of Americans. Since they are closely linked in terms of administration and eligibility, some people may wonder – are your Medicare and Social Security numbers identical?

The short answer is no, Medicare and Social Security numbers are different identifiers assigned by each program. But it wasn’t always this way. Let’s take a closer look at the history of Medicare ID numbers, why they changed, and how Medicare and Social Security numbers are now handled.

Medicare ID Numbers: Past and Present

Originally when the Medicare program first launched in 1966, beneficiaries were not given separate Medicare identification cards or numbers. Their Social Security number was used for Medicare identification purposes.

For many decades, Social Security numbers were listed on red, white, and blue Medicare cards distributed to each enrollee. This number was called the Health Insurance Claim Number (HICN) and used for processing Medicare claims by providers.

However, concerns began growing about potential identity theft risks associated with having Social Security numbers displayed on Medicare cards.

To help protect beneficiary privacy and security, legislation was passed requiring the program to phase out use of Social Security numbers on Medicare cards.

Beginning in April 2018, the Centers for Medicare and Medicaid Services (CMS) started mailing out newly redesigned Medicare cards to all enrollees. These feature a new randomly generated Medicare Beneficiary Identifier (MBI) instead of the Social Security number.

Now every Medicare beneficiary has a unique MBI número that is different from their Social Security number. MBIs contain a combination of numbers and uppercase letters.

Some key facts about the transition to new Medicare numbers:

  • The changeover took place over a 3 year period, completing in April 2021.

  • Social Security numbers are no longer shown on redesigned Medicare cards.

  • Old Medicare cards with Social Security numbers remain valid until expiry.

  • New MBIs do not need to be shared with providers after initial enrollment.

  • People with Medicare should protect their new MBI like they would a credit card number.

Why Medicare Needed Separate Numbers

There were a few compelling reasons why federal lawmakers and Medicare administrators ultimately decided that Social Security numbers needed to be removed from Medicare cards:

Identity theft – Displaying Social Security numbers on Medicare cards substantially increased the risk of this highly sensitive personal data being obtained and used illegally. Separate Medicare numbers help minimize this threat.

Fraud prevention – Use of Social Security numbers made it easier for unscrupulous actors to fabricate Medicare enrollment and commit healthcare fraud. Unique MBIs per enrollee mitigate this issue.

Data security – Social Security numbers on Medicare cards were vulnerable to access and exploitation by those handling beneficiary records in the complex web of healthcare administration. Unique MBIs better protect data.

Beneficiary privacy – Beneficiaries had little control over their Social Security number displayed on Medicare cards given to providers. MBIs give enrollees more privacy over access to their identification data.

Program integrity – The Social Security Administration recommended removal of Social Security numbers from Medicare cards to uphold responsibilities as stewards and protect beneficiaries.

Legislative mandate – The Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) legally required transition from Social Security numbers to new Medicare identifiers.

How Providers Use Medicare Numbers

Under the old system using Social Security numbers as Medicare IDs, healthcare providers would use this number when submitting Medicare claims for payment after treating enrollees.

With the transition to unique MBIs, providers now track each patient’s distinct Medicare number internally and use it for billing purposes after the initial enrollment. MBIs cannot be changed or chosen by patients.

Patients simply provide the MBI when first signing up for Medicare and seeking care from providers. The CMS system pairs each provider’s records of a given patient with that MBI. Patients do not need to share the actual MBI again once established in provider systems.

For coordination of benefits with other insurers, providers may still need a patient’s Social Security number, along with their MBI. Overall, the MBI is now their core identifier for Medicare purposes.

How Medicare Beneficiaries Get New Numbers

During the 3-year transition period from 2018 to 2021, CMS automatically mailed out the newly redesigned Medicare cards with MBIs to all people with Medicare nationwide.

Those eligible did not need to take any action to get their new Medicare number. The cards were sent in phases based on geographic location and age groups.

The new Medicare cards include names, MBIs formatted like ####-####-####A, eligibility dates, and notations if the individual has Part A, Part B, or both.

People becoming newly eligible for Medicare after 2021 are provided with the updated MBI cards during the enrollment process. They no longer get cards showing their Social Security number.

If a replacement Medicare card is ever needed due to loss or damage, beneficiaries can:

  • Log into or create their secure Medicare account to print or order a replacement card.

  • Call Medicare at 1-800-MEDICARE (1-800-633-4227) to request a new card sent via mail.

  • Contact the Railroad Retirement Board for a replacement if receiving RRB benefits.

Protecting Your New Medicare Number

With Social Security numbers no longer displayed on the cards, proper handling of the new Medicare numbers is essential. Here are some key tips:

  • Treat your MBI like you would a credit card number or other private personal information. Never share with untrustworthy sources.

  • Only provide your MBI to healthcare providers for coordination of care and billing purposes.

  • Do not give out your MBI over the phone or to random callers claiming to be from Medicare.

  • Keep your Medicare card in a secure place and know where to access if needed.

  • Be alert to scams asking for your MBI or other personal details.

  • Report concerns about potential misuse of your MBI or Medicare identity theft immediately.

  • Destroy old Medicare cards with Social Security numbers when they expire to avoid misuse.

  • Contact Medicare promptly if you suspect your MBI may have been compromised and need a new number.

Careful stewardship of new MBIs by both providers and beneficiaries helps maximize privacy protections intended under this important Medicare identifier transition.

Key Takeaways

  • Originally Medicare used Social Security numbers as the Health Insurance Claim Number (HICN) until recent changes.

  • New randomly generated Medicare Beneficiary Identifiers (MBIs) now replace Social Security numbers on redesigned cards.

  • The Medicare program transitioned to using unique MBIs to improve beneficiary privacy and security.

  • Medicare numbers are now different from Social Security numbers, with no common digits or overlap.

  • Providers use MBIs for coordinating care and billing after initial patient enrollment.

  • Medicare beneficiaries should protect their new MBIs similar to other personal identification numbers.

While Medicare and Social Security programs remain connected in other ways, the identifiers assigned to beneficiaries by each are now distinct and separate. This change ensures greater privacy and data protections for the millions of Americans eligible for Medicare.

How to Find Your Medicare ID Number (Without Your Card)


Is my Medicare number the same as my SSN?

It used to be that your Medicare number was often the same as your Social Security number. That’s no longer true. To add extra security, the government assigns every beneficiary a unique number that is different from their Social Security number.

Is my Medicare number on my Social Security account?

To find your Medicare number, sign in to your Social Security account and view your benefit verification letter.

Does Medicare count as Social Security?

Social Security and Medicare are distinct programs serving older and disabled Americans, but they have an important commonality: Social Security handles enrollment for Medicare Part A (hospital insurance) and Part B (medical insurance).

What are Medicare numbers?

A Medicare MBI number contains 11 characters, which are randomly generated without underlying meaning. The MBI number is a string of numbers and upper-case letters, which will include an arbitrary combination of digits (1 through 9) and any letters in the alphabet except B, I, L, O, S, and Z.

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