Medicare fax number: which number to use for what

There is no single, general Medicare fax number. Medicare's own contact page lists only the phone line, 1-800-MEDICARE (1-800-633-4227), and a mailing address - the fax numbers that do exist each belong to one specific job, like signing up for Part B or answering a Medicare recovery letter. Once you know which number fits your case, you can send the pages from your phone with HonestFax - no fax machine needed.

This guide lists the official Medicare fax numbers we could confirm on medicare.gov, cms.gov and ssa.gov, what each one is for, and what Medicare does not take by fax.

Medicare fax numbers, by task

What you're sending	Where to fax it
Part B sign-up forms (CMS-40B, CMS-L564) and proof of employer coverage	Your local Social Security office's fax number - Medicare enrollment goes through SSA
A request for Medicare information in braille, large print or another accessible format	1-844-530-3676 (CMS, Customer Accessibility Resource Staff)
Coordination of benefits - reporting other insurance, a case, correspondence (BCRC Data Collections)	1-833-844-1427
Non-group health plan recovery started by the BCRC (liability, no-fault, workers' comp, self-calculated or fixed percentage option)	1-833-844-1540
Workers' Compensation Medicare Set-Aside proposal or final settlement	1-833-844-1428
Group health plan recovery (Commercial Repayment Center)	1-844-315-4313
Non-group health plan recovery started by the CRC	1-844-315-7627

The recovery numbers come from CMS's "Coordination of Benefits & Recovery" contacts page. CMS adds an important note at the top: if you got a recovery letter, send your documents to the return address printed on that letter. The letter beats any list, including this one.

How to fax Medicare Part B forms to Social Security

Signing up for Medicare, replacing a Medicare card and changing your address are handled by the Social Security Administration, not by Medicare. SSA's blog post on Part B enrollment says you can fax or mail the completed CMS-40B (Application for Enrollment in Medicare - Part B) and CMS-L564 (Request for Employment Information) to your local Social Security office.

1. Find your office's fax number in the ssa.gov Field Office Locator - our Social Security fax number guide shows exactly where it is on the office's page.
2. On the CMS-40B, write in the remarks section the month and year you want Part B to start ("I want Part B coverage to begin MM/YY"), as SSA's instructions say.
3. If you're enrolling because employer coverage is ending, include one proof document - SSA lists W-2s with pre-tax medical contributions, pay stubs showing health insurance deductions, a health insurance card with an effective date, explanations of benefits, or premium receipts.
4. Add a cover sheet with your name, phone number and the page count.

SSA also offers the same Part B application online. Faxing makes sense when you already have the paper forms signed, or you can't upload them.

What Medicare doesn't take by fax

• Claims from people with Original Medicare. Medicare.gov says your doctor or supplier is required to file claims for you. In the rare case you file your own (form CMS-1490S), you mail it with the itemized bill to the address for your state listed in the form - there is no fax option on that page.
• General questions. Billing, claims and records questions go to 1-800-MEDICARE or your secure Medicare account. The accessible-formats fax (1-844-530-3676) is only for requesting materials in another format.
• Medicare Advantage and Part D plans. If you have a Medicare Advantage (Part C) or drug plan, it is run by a private company. Use the fax or address your plan gives - the number is usually on your member card or the plan's letter, not on medicare.gov.

For doctors and suppliers: providers work with their Medicare Administrative Contractor (MAC), and each MAC publishes its own phone and fax numbers on its website - for example, CGS lists a "Phone / FAX" page for its Jurisdiction 15 Part B (Kentucky and Ohio) customers. Use the MAC for your state and the form you are sending.

How to fax Medicare forms from your iPhone

You don't need a fax machine, a print shop or a landline. With HonestFax:

1. Install HonestFax and open the New Fax tab. No account and no email address.
2. Add a cover page: your full name, a phone number, what the pages are and how many. Leave off anything the form doesn't ask for. Our cover sheet guide shows a clean layout.
3. Sign the paper form first, then scan it with the camera, or add the PDF from Files. Small print and checkboxes need a flat page and good light - see how to scan documents for a fax.
4. Choose United States and enter the fax number for your task from the table above (or your SSA office's number for Part B).
5. The price shows before you send - each page is 1 credit. If the line is busy, the app retries for about 30 minutes, and if the fax still fails, the credits come back automatically.
6. When it says Delivered, the receiving fax machine accepted every page. Keep that record with the time and the page count.

The full walkthrough with screenshots is in how to send a fax from your iPhone. For referrals and records going to a doctor's office instead, see faxing medical forms to a doctor's office.

Frequently asked questions

Does Medicare have a fax number? Not a general one. Medicare's contact page gives a phone number and a mailing address. CMS publishes fax numbers only for specific tasks, like accessible-format requests (1-844-530-3676) and Medicare recovery and coordination of benefits (listed above).

Can I fax my Medicare application? For Part B, yes - SSA says you can fax or mail the CMS-40B and CMS-L564 to your local Social Security office. Use that office's fax number from the ssa.gov Office Locator.

What is the Medicare fax number for claims? If you file your own claim under Original Medicare, medicare.gov says to mail it to the address for your state listed in form CMS-1490S. Doctors and suppliers send claims through their Medicare Administrative Contractor.

Is 1-800-633-4227 a fax number? No. 1-800-MEDICARE (1-800-633-4227) is the phone line, open 24 hours a day, 7 days a week except some federal holidays. TTY users call 1-877-486-2048.

How do I know Medicare got my fax? A delivered fax means the receiving machine took every page at a time you can show. Processing comes later, so call if you don't hear back - more in how to confirm a fax was received.

Checked on November 9, 2026: medicare.gov, "Contact Medicare" (1-800-MEDICARE 1-800-633-4227, TTY 1-877-486-2048, mailing address; no fax listed). medicare.gov, "Accessibility & Nondiscrimination Notice" (fax 1-844-530-3676 for accessible-format requests). cms.gov, "Coordination of Benefits & Recovery - Contacts" (page last modified 12/17/2024: BCRC Data Collections fax 1-833-844-1427; BCRC NGHP recovery fax 1-833-844-1540; WCMSA fax 1-833-844-1428; CRC GHP fax 1-844-315-4313; CRC NGHP fax 1-844-315-7627; send to the return address on your recovery letter; SSA handles enrollment, card replacement and address changes). ssa.gov blog, "Sign up for Medicare Part B Online, by Fax, or by Mail" (October 17, 2024: fax or mail CMS-40B and CMS-L564 to your local office; remarks line; proof documents). medicare.gov, "Filing a claim" (providers file claims; CMS-1490S mailed to the address in the form; 12-month limit). cgsmedicare.com, "J15 Part B Customer Service" (updated 08.04.2026, Phone / FAX page). Numbers can change - check the source on the day you send. HonestFax retries and automatic refund as shown in the app.