Where Can You Find Your Medicare Claim Number?

In this article...
  • Your Medicare claim number, or Medicare Beneficiary Identifier (MBI) is an 11-character number Medicare uses to identify you. Learn how to find your number and how to use it to file a Medicare claim or track your Medicare claim status.

On the front of your Medicare card is a number that is 11 characters long, consisting of numbers and uppercase letters. This is your Medicare claim number, also referred to as a Medicare Beneficiary Identifier (MBI). 

To avoid confusion between letters and numbers, Medicare does not use the letters S, L, O, I, B or Z. So if your Medicare claim number contains an O, it is the number “0” and not the letter “O.”

Medicare previously used a person’s Social Security number to file claims. But over the course of 2018 and 2019, Medicare issued new cards to all beneficiaries with a randomly assigned number that is unique to each person. This was done to help protect the personal identifying information of Medicare beneficiaries and to help minimize identity theft and other forms of fraud.

If you have lost your Medicare card, log into MyMedicare.gov (or create a new account) to print another temporary copy. You may also call 1-800-MEDICARE (1-800-633-4227) and follow the prompts for help replacing a lost or stolen card

Using Your Medicare Number to File a Claim

Medicare beneficiaries do not typically have to file claims on their own. A health care provider has one year from the day of service to file a claim on behalf of a patient. But if your claim is not filed in a timely manner, you may contact the provider to request that they file the claim. 

If they still don’t file the claim soon after your request, you may file the claim yourself by gathering and completing the Patient Request for Medical Payment (CMS-1490S) form along with an itemized bill from the health care provider and a letter explaining your reason for filing the claim. 

In order to submit the claim, you will need to look up the appropriate Medicare Administrative Contractor (MAC). MACs are private health care insurers that have been awarded a geographic jurisdiction to process Original Medicare (Medicare Part A and Part B) claims.    

You may find the appropriate MAC for your claim on this page of the federal Medicare website by selecting your state and choosing between a Part A or B claim, a durable medical equipment (DME) claim or a home health and hospice claim. 

If you have questions about filing a claim, you can call 1-800-MEDICARE (1-800-633-4227). 

Can I See My Medicare Claims Online?

You may view the status of your Medicare claims online at MyMedicare.gov. Claims are typically available for viewing within 24 hours of submission. You may even use the “Blue Button” within the MyMedicare.gov portal to download all of your personal health information and all your Medicare claims in a single data file. 

You will also receive a Medicare Summary Notice (MSN) in the mail every three months that will detail the results of all claims for that f