If you’re enrolled in Medicare and also have other health coverage—like a group health plan, retiree insurance, or Medicaid—it’s important to know which insurer pays your claims first. This process, called Coordination of Benefits (COB), ensures your medical bills are handled correctly.
Under COB rules, one plan acts as your primary payer, covering most of your health care costs. The secondary payer may cover any remaining eligible expenses not paid by the primary plan. This process helps make sure each payer meets their payment responsibilities and that your claims are processed accurately and on time.
How Medicare Works with Other Insurance
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The primary payer pays first, up to its coverage limits.
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The secondary payer steps in for costs the primary plan doesn’t cover—but may not pay all remaining amounts.
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If your group or retiree plan is secondary, you might need Medicare Part B before that plan will pay.
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If your primary insurer doesn’t pay your claim promptly (usually within 120 days), Medicare may make a conditional payment—a temporary payment it later recovers from the primary payer.
Conditional Payments Explained
A conditional payment is one Medicare makes for services that another insurer should pay for. This protects you from having to pay out-of-pocket while the claim is sorted out. If you later receive a settlement, judgment, or other payment from that insurer, Medicare must be reimbursed for the conditional payment it made.
Who Pays First?
Medicare’s role—primary or secondary—depends on your type of coverage and circumstances. Medicare is typically the primary payer when:
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You have only Medicare and Medicaid.
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You’ve declined group health plan coverage.
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Your group health plan doesn’t cover a service that Medicare does.
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You’ve used up your group plan coverage.
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You’re 65+ and covered by an employer plan with fewer than 20 employees.
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You’re retired and have retiree health coverage.
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You’re covered by Medicare and COBRA.
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You’re disabled and your employer’s group plan has fewer than 100 employees.
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You have end-stage renal disease (ESRD) and have had Medicare for more than 30 months.
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You have TRICARE and are not on active military duty.
For a full list of who pays first, visit Medicare.gov or check the CMS guide Medicare & Other Health Benefits: Your Guide to Who Pays First.
How Medicare Knows About Other Coverage
The Benefits Coordination and Recovery Center (BCRC) manages information about your other insurance. The BCRC:
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Tracks and updates other coverage you may have.
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Determines who pays first.
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Manages repayments if Medicare issues conditional payments.
Medicare doesn’t automatically know when you have other coverage. Your provider, employer, or insurer may ask for your current insurance details so they can update Medicare’s records. You can also share this information directly by calling the BCRC at 1‑855‑798‑2627.
If Your Coverage Changes
Always tell your provider and health plan if your insurance changes. Insurers are required to report changes to Medicare, but updates can take time to appear in the system. You can also contact the BCRC to ensure your coverage information is correct, helping your claims get paid properly.