My claim was denied because I have other insurance. Who pays first?

Health insuranceDeniedChecked Nov 6, 2026

From K.Actuary, founded by Sangmin Kwon, ASA · sources checked 2026-11-06 · Source: Medicare.gov View original ↗

In short

When you have two plans, one pays first.
Ask each plan who it thinks pays first and why.
Send the second plan the first plan's statement.

What this means

When you have two health plans, one pays first. Medicare.gov says the first payer pays up to its limit [1]. Then it sends the rest to the second payer [1]. This order is called coordination of benefits [1].

CMS says the same for people who have Medicare and other insurance [2]. If the insurance company does not pay the claim promptly (usually within 120 days), your doctor or other provider may bill Medicare [1]. If a plan denies the claim, an employer group plan must give you at least 180 days after the notice to appeal [3].

Your next step

Find out which plan the rules make primary, because coordination of benefits rules decide which pays first [2]. If an insurance company does not pay promptly (usually within 120 days), your doctor or other provider may bill Medicare [1]. If a plan denies the claim, an employer group plan must give you at least 180 days after the notice to appeal [3].

Check it yourself

Open the first source above and read the part quoted. Your own policy papers hold details these sources do not give: "Don't know yet" for your case.

Where this comes from (3)

[1] Medicare.gov · checked 2026-11-06
The "primary payer" pays up to the limits of its coverage, then sends the rest of the balance to the "secondary payer." If the “secondary payer” doesn't cover the remaining balance, you may be responsible for the rest of the costs. If your group health plan or retiree coverage is the secondary payer, you may need to sign up for Medicare Part B before they'll pay. This order of payment is called "coordination of benef…
[2] CMS · checked 2026-11-06
If a beneficiary has Medicare and other health insurance, Coordination of Benefits (COB) rules decide which entity pays first
[3] GovInfo · 29 CFR § 2560.503-1 «Claims procedure: appeal time» · paragraph (h)(3)(i) · checked 2026-11-06
Provide claimants at least 180 days following receipt of a notification of an adverse benefit determination within which to appeal the determination

How we found this

We matched your question to 3 official sources, quoted the exact lines, and re-checked each quote against its source on 2026-11-06.

What we don’t know yet

Your own plan or notice may say something different. If your letter cites another rule, send it and we will look again.

Every answer is checked against the official rule it quotes.

Information only — not legal advice. Your plan, insurer or agency decides.

This answer quotes the official sources listed above, with the date we checked them. Your own policy, notice and state rules control. We are not your lawyer or your insurer. We don’t file, argue or negotiate claims for you — you send any letter or form yourself.

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