To submit a Medicare claim for reimbursement, complete form CMS-1490S (“Patient’s Request for Medical Payment”), attach an itemized bill from your provider, and mail it to the Medicare Administrative Contractor for your state within one year of the date of service. Most beneficiaries never do this because providers are required to file for them. You’d only take it on yourself when a provider refuses, or when care happened somewhere outside the normal U.S. billing system.
When You’d File the Claim Yourself
The usual reason is that a provider didn’t submit the claim they were supposed to submit. Medicare-enrolled providers are required to bill Medicare on your behalf, and when that breaks down and you’ve paid out of pocket, the CMS-1490S is how you get reimbursed for the covered portion.1Medicare.gov. Filing a Claim
Non-participating providers are enrolled in Medicare but haven’t agreed to accept Medicare’s approved amount as full payment on every claim. They can collect from you at the time of service, but they’re still generally expected to submit the claim to Medicare so you can be reimbursed.2Medicare.gov. Does Your Provider Accept Medicare as Full Payment? If one won’t, filing yourself is the fix.
One boundary worth knowing before you start: providers who have opted out of Medicare entirely require you to sign a private contract agreeing to pay the full cost yourself, and Medicare will not reimburse you for those services. The narrow exception is emergency or urgent care from an opt-out provider when you haven’t previously signed a private contract with them, in which case Medicare can still pay and the provider is required to submit the claim.3eCFR. 42 CFR Part 405 Subpart D – Private Contracts – Section 405.440
The other common scenario is a foreign hospital. U.S. hospitals must submit claims to Medicare; hospitals outside the country are not required to. If your care abroad falls under one of Medicare’s limited coverage situations and the hospital won’t file, the claim is yours to submit.4Medicare.gov. Travel Outside the U.S.
The One-Year Deadline
You have one calendar year from the date of service to get the claim to Medicare. Care received on March 15, 2026 must reach your Medicare contractor by March 15, 2027. If the deadline falls on a weekend or federal holiday, it moves to the next business day.5eCFR. 42 CFR 424.44 – Time Limits for Filing Claims Miss it and Medicare will deny payment.
Extensions exist for narrow situations such as a serious illness that prevented filing, destruction of records in a natural disaster, or incorrect instructions given to you by Medicare. You’ll have to explain the delay and provide evidence.
What to Gather Before You Start
The document that matters most is an itemized bill from the provider. It has to show each service performed, the date of each service, the charge for each service, and the provider’s name and address. A credit-card receipt or a lump-sum statement isn’t enough. You need line-by-line detail.
You also need your Medicare card, because your name and Medicare number on the form must match it exactly. Have the provider’s full name, address, and, if you can find it, the 10-digit National Provider Identifier (NPI) that appears on many medical bills and explanations of benefits. If your itemized bill lists diagnosis or procedure codes, keep them handy; including them helps Medicare process the claim faster.
Download the CMS-1490S from the CMS website, or request a paper copy by calling 1-800-MEDICARE (1-800-633-4227).6Centers for Medicare & Medicaid Services. CMS-1490S – Patient’s Request for Medical Payment
Filling Out the CMS-1490S
The form runs two pages. The top asks for your name, Medicare number, address, and phone number; enter them exactly as they appear on your Medicare card, because a single transposed digit in the Medicare number can push processing back by weeks.
The middle section is where the itemized bill gets transferred: dates of service, description of each service, and the charge for each item, plus diagnosis or procedure codes if your bill shows them. The bottom is your signature and date, certifying the information is accurate.
Three mistakes send claims back. Leaving provider information blank, because Medicare needs it to verify the claim. Forgetting to sign. Attaching a summary bill instead of an itemized one. Check all three before you seal the envelope.
Where to Mail It
Beneficiary-submitted claims go by mail. Medicare does not accept the CMS-1490S electronically or through any online portal.1Medicare.gov. Filing a Claim The completed form goes to the Medicare Administrative Contractor (MAC) assigned to your state. Each state has a specific MAC, and the correct address is in the MAC Address Table included with the CMS-1490S packet.6Centers for Medicare & Medicaid Services. CMS-1490S – Patient’s Request for Medical Payment You can also look up your MAC through the CMS contractor directory at cms.gov.
Send a copy of the itemized bill and any supporting documents with the form, and keep the originals. Photocopy the whole packet before mailing so you have a record of what you sent. The CMS-1490S instructions ask you to allow at least 60 days for Medicare to receive and process the claim.
What You Actually Get Back
Filing doesn’t return every dollar you spent. For Original Medicare (Part B) services, you first have to meet the annual Part B deductible, which is $283 in 2026.7Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles After that, Medicare generally pays 80% of the Medicare-approved amount, and you’re responsible for the remaining 20% coinsurance.8Medicare.gov. Costs
Non-participating providers add a second layer. They can charge up to 115% of the Medicare fee schedule amount, a ceiling called the limiting charge.9eCFR. 42 CFR 414.48 – Limits on Actual Charges of Nonparticipating Suppliers Medicare’s 80% is calculated on its approved amount, not on the higher price you paid. The gap is yours.
Say Medicare’s approved amount for a service is $200. A non-participating provider can charge you up to $230. Medicare reimburses 80% of $200, or $160. You end up responsible for $70. Doing that math before you file keeps the reimbursement check from being a disappointment.
Tracking the Claim and Reading Your MSN
You can check the status of a submitted claim by logging into your Medicare.gov account. The formal record arrives as a Medicare Summary Notice (MSN), mailed every three months if you received Part A or Part B services during that period.10Medicare.gov. Medicare Summary Notice
The MSN is not a bill. It shows what was billed, what Medicare approved and paid, and the maximum amount you may owe. Read it carefully. If a service you received isn’t listed or an amount looks wrong, call 1-800-MEDICARE. Catching errors early is much easier than untangling them months later.
If the Claim Is Denied
A denial isn’t final. Medicare has a five-level appeals process, and you have 120 days from the date you receive the initial decision to request the first step, a redetermination by your Medicare contractor.11Medicare.gov. Filing an Appeal Most beneficiary disputes get resolved at the first or second level. The specific appeal rights that apply to your claim are printed on the MSN itself.12U.S. Department of Health and Human Services. The Appeals Process