Search for "Medicare fax number" and you will find dozens of numbers, most of them wrong for your situation. That is not because Medicare hides its fax lines. It is because Medicare is not one office. Original Medicare claims are processed by a dozen regional contractors, and Medicare Advantage and Part D plans each run their own appeals departments.

This guide to how to fax documents to Medicare explains which forms are commonly faxed, how to work out which office should receive yours, and the verified numbers for one contractor as a worked example.

  • No single number exists. Your notice tells you who handles your claim.
  • Appeals and representative forms are the documents most often faxed.
  • The fax date is the filing date, so the confirmation matters.

Table of Contents

Why there is no single Medicare fax number

CMS does not process most Original Medicare claims itself. It contracts that work to Medicare Administrative Contractors (MACs), each responsible for a geographic jurisdiction. CMS lists 12 A/B MAC jurisdictions, which handle Part A and Part B claims, and four DME MAC jurisdictions, which handle durable medical equipment.

Each contractor runs its own fax lines, and within a contractor different departments use different numbers: redeterminations, reopenings, medical review, provider enrollment. A redetermination faxed to the wrong contractor, or to the right contractor's enrollment line, is not an appeal anyone is working on.

Medicare Advantage (Part C) and Part D drug plans are different again. If you have one of those plans, your appeal goes to the private insurer running the plan, not to a MAC.

Forms commonly faxed to Medicare

Fax is used for a fairly narrow set of documents:

  • Redetermination requests (first-level appeals). You can use Form CMS-20027, Medicare Redetermination Request Form, or a written request containing the beneficiary's name, Medicare number, the specific services and dates being appealed, the name of the party or representative, and an explanation of why you disagree.
  • Form CMS-1696, Appointment of Representative. If a family member, advocate, or attorney is handling the appeal for you, this form (or another written document with the same required elements) goes in with the appeal. CMS describes the appointment as valid for one year from the date both you and your representative have signed.
  • Written reopening requests for clerical errors on a processed claim, where the contractor lists a fax line for them.
  • Documentation the contractor requested, such as medical records for a review.

What generally cannot be faxed: new claims. Noridian's fax directory states plainly that it cannot accept initial or new claim forms by fax. Claims go through the provider's normal billing channel.

How to find the right fax number

Work through these in order and stop at the first one that gives you a number:

  1. Your denial or notice letter. If the letter about your claim includes a fax number for appeals, use it. It routes to the unit already handling your case.
  2. Your Medicare Summary Notice (MSN). Medicare.gov says to send a redetermination to the contractor whose address appears on the last page of your MSN. The MSN tells you which contractor; that contractor's website gives the fax number.
  3. The contractor's own website. Every MAC publishes a contact page. Look for a fax directory and pick the line labelled for redeterminations or appeals, not general inquiries.
  4. 1-800-MEDICARE. If you are unsure which contractor or plan handles your claim, call Medicare and ask.

Do not use a number from a third-party list. CMS reassigns contracts periodically, and contractors change fax lines.

Example: Noridian fax numbers

As a worked example, here are the fax numbers Noridian Healthcare Solutions publishes for its Part B jurisdictions. Noridian is the A/B MAC for Jurisdiction E (California, Hawaii, Nevada, American Samoa, Guam, and the Northern Mariana Islands) and Jurisdiction F (Alaska, Arizona, Idaho, Montana, North Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming).

Verified October 2026 against Noridian's JE Part B and JF Part B fax directories:

Purpose (JE and JF Part B) Fax number
Redeterminations, written reopenings, general written inquiries 701-277-7852
Medical review: post-payment documentation requests 701-277-6977
Provider enrollment 701-277-7868

These are Part B numbers for those two jurisdictions only. Part A claims, DME claims, and every other state use different contractors and different numbers. Noridian also asks that each claim, inquiry, or response be sent as a separate fax.

If your MSN names a different contractor, go to that contractor's website and find the equivalent line.

How to fax a Medicare appeal, step by step

  1. Check the deadline. For Original Medicare, a redetermination must be requested within 120 days of receiving the initial determination. Receipt is presumed to be five days after the date on the notice. Your MSN states the date.
  2. Complete Form CMS-20027 or write a request with all the required details. Missing a required element, such as the dates of service, slows everything down.
  3. Add Form CMS-1696 if a representative is filing. Both you and the representative sign it.
  4. Attach a copy of the MSN or denial notice, with the disputed items circled, plus any supporting medical records.
  5. Put your name and Medicare number on every page. Pages can separate during scanning.
  6. Fax to the redeterminations line of the contractor named on your MSN.
  7. Keep the confirmation. CMS guidance treats the date a contractor receives a fax as the filing date, so the transmission record is your evidence that you met the deadline.

In most cases the contractor issues its decision within 60 days of receiving the request.

You do not need a fax machine for any of this. You can send a fax online from a browser for a one-time payment, with no subscription and no account, and get the delivery confirmation by email.

Medicare Advantage and Part D appeals

If you have a Medicare Advantage plan or a Part D drug plan, the appeal goes to the plan. Each insurer publishes its own appeals fax numbers, often split by standard versus expedited requests and by plan type, and the deadline is set out in the denial notice. UnitedHealthcare, for example, gives members 65 days from the date of an unfavourable Part D determination to file an appeal.

The right number is in three places: the denial notice, your plan's Evidence of Coverage, and the appeals page of the insurer's website. Our guide to faxing insurance companies lists verified appeals numbers for several large Medicare Advantage and Part D plans.

Privacy when faxing Medicare documents

Medicare appeals carry your Medicare number and medical details. HHS guidance on health information says that a reasonable safeguard when faxing to a number you do not use regularly is to confirm the number with the recipient first. The same principle protects you: a single wrong digit sends your records to a stranger's machine.

Faxio stores uploaded documents encrypted and uses them only to render and transmit your fax, as set out in our privacy policy.

Faxing Medicare comes down to sending the right form to the contractor or plan named on your notice, before the deadline, and keeping the confirmation. Get the number from the notice or the contractor's site, not from a list, and fax remains one of the fastest ways to file.

Send your Medicare fax now →

Frequently asked questions

What is the Medicare fax number?

There is no single national Medicare fax number. Original Medicare claims and appeals are handled by regional Medicare Administrative Contractors, and Medicare Advantage and Part D appeals go to your plan. Use the address on your Medicare Summary Notice or denial letter, and take the fax number from that contractor's or plan's official website.

Can I fax a Medicare appeal?

Usually, yes. CMS guidance treats an appeal request received by fax as a written request, and its filing date is the date the contractor receives the fax. Contractors are not required to offer fax, though, so confirm your contractor lists a fax line for redeterminations before relying on it.

How long do I have to file a Medicare redetermination?

For Original Medicare, 120 days from the date you receive the initial determination, which is presumed to be five days after the date on the notice. Your Medicare Summary Notice states the deadline that applies to you.

Where do I send Form CMS-1696?

Form CMS-1696, Appointment of Representative, is not sent on its own to a central office. Attach it to the appeal or request it supports, and send it to the same contractor or plan handling that appeal.

Can I fax a new Medicare claim?

Generally no. Noridian, for example, states on its fax directory that it cannot accept initial or new claim forms by fax. Claims are submitted by providers through the normal claims process; fax is for appeals, reopenings, and requested documentation.

Sources