Medicare (Original) Timely Filing Limit
Medicare (Original) allows 12 months for initial claim submission, counted from date of service.
- Initial claims
- 12 months
- Counted from
- Date of service
- Appeals
- 120 days from initial determination (redetermination)
- Category
- Government
Published default as of 2026 — individual participation agreements and plan documents override payer defaults. Always verify against your contract and the current provider manual.
What billers should know
Set by statute (42 CFR § 424.44) — one calendar year from the date of service. Very few exceptions apply (administrative error, retroactive entitlement, dual-eligible retro enrollment). Claims past the limit are denied with CO-29 and cannot be billed to the patient.
Missed the Medicare (Original) deadline?
- 1
Pull your proof of timely submission — clearinghouse acceptance reports (277CA), payer portal submission logs, or EDI acknowledgments. If the claim was submitted in time and lost or rejected downstream, most payers must reopen it.
- 2
The denial arrives as CO-29 — appeal with documentation, citing the original submission date and any payer-side errors (wrong member ID on file, retroactive eligibility, COB delays).
- 3
If the miss is genuinely yours, write it off correctly: timely filing denials are a contractual adjustment — billing the patient for them violates most network agreements.
- 4
Fix the root cause: charges should leave the door within 48–72 hours of the encounter, with a worklist for anything unbilled after 7 days.
OakClaim files every claim within 48 hours — no deadline math required.
Free audit shows how much late filing and unworked denials are costing you.