Medicare fax number: where each kind of Medicare paperwork goes

Where it goes

• Enrolling in Part A or B (CMS-40B, CMS-L564): your local Social Security office. See Medicare Part B enrollment fax.
• Original Medicare appeal, level 1 (redetermination): the Medicare Administrative Contractor whose address is on the last page of your Medicare Summary Notice. Medicare.gov describes mailing it; whether that contractor takes faxes, and its number, is on the contractor’s own website.
• Part D drug plan appeals: your plan, at the fax number in its denial notice. The next level goes to the independent reviewer: see Medicare Part D appeal fax.

How to fax it

1. Work out where it goes from the list above.
2. Include your name, address and Medicare Number, and for an appeal the items and dates you disagree with and why.
3. Send it from dimefax.com/send to the number from your notice or the contractor’s site.
4. Keep the delivered confirmation. Dimefax shows the date and time it went through.

Dimefax costs 10¢ a page and you’re only charged if the fax goes through. On the web, page credits come in packs of 50 for $4.99, 100 for $9.99 or 200 for $19.99; the Dimefax iPhone app also sells 10 for $0.99. Credits you don’t use stay in your account and last as long as you fax once a year.

Where these numbers come from

• Medicare.gov: Talk to someone
• Medicare.gov: Appeals in Original Medicare
• Medicare.gov: Appeals in drug plans

Dimefax isn’t part of, or endorsed by, Medicare. We copied these numbers from medicare.gov on November 11, 2026. Agencies change their numbers: if your letter, notice or form gives a different one, use that.