When Is Medicare Primary or Secondary Health Insurance?

Reviewed by: Selah Lee, Licensed Insurance Agent
Key Takeaways
Medicare is the primary payer for beneficiaries who do not have other coverage through plans offered by employers, other groups, or unions, except under certain circumstances.
Once you are eligible for Medicare, you can drop your employer or union health insurance if you’d like to and enroll in Medicare Part B. You will need to show proof of creditable coverage for your time without Part B.
Can I have Medicare and Employer Health Insurance Together?
Yes, you can have both Medicare and employer health insurance together. When you have Medicare and other health insurance or coverage, you have more than one “payer.” In these instances, “coordination of benefits” rules will decide which payer pays first.
Medicare is the primary payer for Medicare beneficiaries who are on employer plans if there are less than 20 employees. However, if the beneficiary is on an employer plan with 20 or more employees, that plan will serve as the primary payer,
If you have specific questions about your company’s health insurance, contact your benefits administrator, insurer, or plan provider. If you have any questions on which of your health insurance plans is primary, call the Benefits Coordination & Recovery Center (BCRC) at 1-855-798-2627.
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Does Medicare Cover Deductibles and Copays as Secondary Insurance?
The downside of having two insurance plans (group and Medicare) is that you pay two sets of premiums and deductibles. Your secondary insurance will not pay toward your primary health insurance deductible, and it’s likely you will still have to pay out-of-pocket costs.
Can I still use my Part A coverage even when I don't have Part B?
Yes, you can use Medicare Part A coverage even if you delay enrollment in Part B. However, unless you have other creditable coverage (like employer coverage) you should enroll in Part B, to avoid penalties in the future.
Are you eligible for cost-saving Medicare subsidies?