Medicare Beneficiary Identifier, or MBI, is a personally identifiable number for Medicare recipients. The MBI has replaced the social security number previously used on Medicare cards to identify the beneficiary.

This new number is used on all Medicare transactions including billing, eligibility status, claims, and appeals. It is assigned to every Medicare member and should be treated as important and confidential.

The MBI replaces the previous SSN-based Health Insurance Claim Number (HICN) and is meant to offer more protection against identity theft and other security threats.

What Is a Medicare Beneficiary Identifier (MBI)?

The new numbers on your Medicare card are meant to securely identify Medicare beneficiaries. The number is made up of 11 different characters that have been generated randomly.

The characters are a combination of numbers and upper-case letters that do not have any hidden or special meaning, unlike the previous HCIN, which was based on an individual’s social security number.

What Is the Health Insurance Claim Number (HICN)?

Previously, Medicare beneficiaries were assigned a Health Insurance Claim Number (HICN) after their enrollment. This was a string of up to 11 characters that were based on the social security number of Medicare recipients. Its purpose was to identify an individual as a Medicare beneficiary.

The HCIN was made up of two parts – the primary beneficiary’s Social Security Number (SSN), and the Beneficiary Identification Code number (BIC). It was displayed on the Medicare card and was used for billing, claims, and to determine the beneficiary’s eligibility for services.

Do you qualify for Medicare if you haven’t worked?
Receiving Medicare benefits even if you haven’t worked is a common concern for many people in the US. Take a look at our guide about what it takes to benefit from Medicare even if you haven’t worked.

Why Was the HCIN Discontinued?

The Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) required the removal of social security numbers from all Medicare cards to help tighten personal security and protect Medicare beneficiaries from identity theft.

The rollout started in 2019 and by January 1, 2020, Medicare transactions were rejected without the new MBI. Since then, HCINs have been considered invalid.

How to Find Your Medicare Beneficiary Identifier

The redesigned Medicare card no longer contains the HCIN. This has been replaced with the MBI, which is printed on the front of your Medicare card under ‘Medicare Number’. You will be able to see that it is made up of a combination of numbers and letters that add up to 11 characters in total.

It should also be printed on most of the documents you receive from Medicare like EOB’s (Explanation of Benefits) and Medicare coverage explainers.

If you don’t have the new reissued card yet, you may request for one by contacting Medicare directly. This can be done by going to or calling the 1-800-MEDICARE toll-free number.

Example of a Medicare Beneficiary Identifier

This beneficiary ID number will look different for every person but will follow the same pattern as displayed in the example. Here’s an example of what a Medicare Beneficiary Identifier will look like on your card.

Example Medicare Beneficiary Identifier

Format of the Medicare Beneficiary Identifier

The MBI is unique for each individual beneficiary but it follows a specific format. Spouses and dependents who had similar HICN’s will have their own unique MBI numbers.

  • The second, fifth, eighth, and ninth characters will always be letters.
  • The first, fourth, seventh, tenth, and eleventh characters will always be numbers.
  • Alphabet characters are all upper case only and exclude the letters S, L, O, I, B, and Z to limit the possibility of confusing those alphabet letters with numbers.

While the Medicare card will display the MBI with dashes, these are not part of the number. Dashes are not entered in the computer systems or in forms.

How Many Numbers Are in My Medicare Beneficiary Identifier?

There will be a total of 11 characters in the MBI and will have 5-7 numbers. Unlike the previous HICN, which corresponds to specific details about the beneficiary, the MBI is auto-generated and has totally random characters that do not mean anything in relation to the specific beneficiary.

Similar to the numbers, the uppercase letters on the MBI do not correspond to anything. They are called “non-intelligent” characters, which means there is no special meaning behind them.

Medicare vs Medicaid
Do you need clarification about the difference between Medicare and Medicaid? Both of these programs can help with healthcare costs, but they have many differences. Check out this explainer article about the differences between Medicare and Medicaid.

In Summary

The Medicare Beneficiary Identifier, or MBI, is the new Medicare card number that’s displayed on the red, white, and blue Medicare card. Unlike the old claim numbers, they are no longer based on the Social Security number of the beneficiary, which means the identity of Medicare recipients is more secure than before the MBI.

This important and confidential number becomes the identification number of a Medicare beneficiary and will be used for billing, claims, and appeals.

Medicare Beneficiary Identifier Frequently Asked Questions

What is the 11-digit Medicare number?

Known as the Medicare Beneficiary Identifier or MBI, the 11-digit number printed on the front of the Medicare card is a form of identification for its beneficiary. It is made up of a string of random letters and numbers that help improve beneficiary personal identity protection.

Is my Social Security Number also my Medicare number?

No, your social security number is no longer part of your Medicare number. The Medicare Beneficiary Identifier (MBI) has replaced the previous Health Insurance Claim Number (HICN), which was based on the individual’s SSN.

Do you automatically get Medicare with Social Security?

If you are already receiving Social Security benefits, you will automatically be enrolled in Medicare Part A once you become eligible at the age of 65. Those who don’t have Social Security benefits will not be automatically enrolled in Medicare and will need to sign up themselves.

How do I replace my Medicare card if it gets lost or stolen?

To replace a lost or stolen Medicare card, you need to report it by calling 1-800-MEDICARE (633-4227). You may also order a replacement card through the Medicare website at

Amie has worked with older adults and their families for the past twenty-plus years of her career. Her senior care knowledge is based on her experience as a social worker, family caregiver, and senior care consultant.

An expert in senior care, Amie has professional and personal experience in senior housing, caregiving, end-of-life care, and more from her 24 years of working with older adults.