Is Medicare Primary or Secondary

Medicare is always primary if it’s your only form of coverage. When you introduce another form of coverage into the picture, there’s predetermined coordination of benefits. The coordination of benefits will determine what form of coverage is primary and what form of coverage is secondary.

The primary coverage will pay first, and the secondary coverage pays second. Below, we’ll go over scenarios when Medicare is primary and when Medicare is secondary.

When is Medicare Primary?

For the most part, when you have more than one form of coverage, Medicare is primary. Some examples include having group coverage through a smaller employer, COBRA, being on inactive duty with TRICARE, or Medicaid. Usually, secondary insurance will only pay if the primary insurance paid its portion first.

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Group Coverage Through Small Employer

If your employer has fewer than 20 employees, Medicare will be your primary coverage and the employer coverage will be your secondary coverage. If you do not enroll in Part B, your employer coverage will not pay their portion of your medical claims. This is why it’s very important to enroll in Medicare with you’re first eligible to do so.

In addition, the employer coverage is not creditable. Therefore, you will incur late enrollment penalties if you don’t enroll in Part B when you’re first eligible. This also applies to a spouse on the group plan.

Also, consider how much you’re paying for employer coverage. Most of the time, Medicare costs a lot less in monthly premiums. Compare both options side by side to see if making Medicare your primary coverage will save you money.


There are scenarios when you’ll have Medicare and COBRA at the same time. The majority of the time, Medicare will be primary and COBRA will be secondary. The exception to this is if your group coverage has special rules that determine the primary payer.

It’s not common for COBRA to be the better option for an individual who’s eligible for Medicare. This is because COBRA is more expensive than Medicare. Once you enroll in Medicare, you can drop your COBRA coverage.

Another key fact to know is that COBRA is not creditable coverage. If you’re eligible for Medicare and do not enroll, you’ll incur late enrollment penalties since COBRA is not considered as good as Medicare. You’ll need to enroll in Medicare within the first eight months you have COBRA, even if your COBRA coverage is active longer than eight months.

Retiree Coverage

When your group employer insurance continues to provide you health insurance after you retiree, you’re receiving retiree coverage. In this scenario, Medicare is primary and your retiree converge is secondary. A lot of times retiree coverage will include prescription drug coverage. If this is the case for you, you probably won’t need to enroll in a Part D prescription drug plan. 

Under 65 and Disabled with Employer Group Coverage

In the scenario you’re under 65, eligible for Medicare due to a disability, and have group employer coverage through a small or medium-sized employer with fewer than 100 employees. Medicare will be your primary payer, while your employer coverage is secondary.

TRICARE for Life

When military retirees and their spouses are eligible for Medicare, they become eligible for TRICARE for Life. For any care you receive at a non-military facility, Medicare pays first. That’s why you need to enroll in Part A and Part B when you become eligible.

However, TFL includes good drug coverage. therefore you don’t need to enroll in Part D. Some TFL beneficiaries choose to enroll in a Medicare Advantage plan due to the extra benefits they may come with. These extra benefits can include dental and vision coverage. In addition, TFL will help cover some of the out-of-pocket costs that come with Medicare Advantage plans.

End-Stage Renal Disease

Individuals diagnosed with ESRD will keep their current employer coverage as primary for the first 30 months. After 30 months, they’ll automatically switch over to Medicare as their primary coverage. This rule also applies to COBRA & retiree insurance.

If you receive Medicare due to ESRD and have a successful kidney transplant, your Medicare eligibility will end after 36 months. If you’re eligible for Medicare due to age or disability, then you will continue to remain enrolled in Medicare even after the kidney transplant.


Medicaid is a state-run federal assistance program assisting low-income Americans. When you become eligible for Medicare and are also eligible for Medicaid, you’re dual-eligible. When you’re dual eligible for both Medicare and Medicaid, Medicare is your primary payer. Medicaid will not pay until Medicare pays first.

If you’re dual-eligible and need assistance covering the costs of Part B and Part D, you could qualify for a Medicare Savings Program to assist you with these costs. Always make sure your provider accepts both Medicare and Medicare before seeking care.

When is Medicare Secondary?

Secondary insurance helps cover out-of-pocket costs left over after your primary coverage pays their portion. There are a few common scenarios when Medicare is secondary. An example includes having group coverage through a larger employer with more than 20 employees.

Group Coverage Through Larger Employer

Whether you have group insurance through the company you work for or your spouse’s employer, Medicare is your secondary coverage when the employer has more than 20 employees. Some Medicare beneficiaries will choose to delay their Part B enrollment if their group coverage is cheaper. However, most of the time after evaluating their coverage they find that Medicare will cost them less and provide better coverage if they let Medicare be their primary coverage.  

Under 65 and Disabled with Larger Employer Group Coverage

If you’re under 65, eligible for Medicare due to a disability, and have group employer coverage through an employer with more than 100 employees, Medicare will be your secondary payer. 


TRICARE pays first for Medicare-approved services at a civilian facility if you’re on active duty, Medicare will pay second. Medicare doesn’t cover treatment provided by a military hospital or federal health care provider.

End-Stage Renal Disease

Medicare will be your secondary coverage if you’re diagnosed with ESRD, have group employer coverage, and have been Medicare-eligible for less than 30 months.

Receiving Workers Compensation 

Your workers’ compensation will pay first if you’re injured or become sick on the job. Medicare will pay second. For any medical services received that are not related to the workers’ compensation claim, Medicare will pay first.

Federal Black Lung Program

If you’re covered under the Federal Black Lung Program, the program will pay first and Medicare will pay second. 

No Coordination of Benefits

When there is no coordination of benefits, the policies will not work together, or complement, one another. Some examples include when you have a Medicare Advantage plan, a Marketplace plan, or veterans benefits. Medicare does not coordinate with these healthcare programs.

Is Medicare Advantage Primary or Secondary?

When you enroll in a Medicare Advantage plan, the carrier pays for your medical care instead of Medicare. Therefore, Medicare is no longer responsible to pay your claims. Your Medicare Advantage plan is your primary, and only, coverage.

Is Marketplace Coverage Primary or Secondary to Medicare?

Marketplace coverage and Medicare do not work together. Once you’re eligible for Medicare, you will lose any subsidies through the Marketplace. The only exception is if you’re not eligible for premium-free Part A. Once you’re enrolled in Medicare, you cannot enroll in a Marketplace plan.

Is Veterans Benefits Primary or Secondary to Medicare?

Medicare and veterans benefits don’t work together; both are primary. When you go to a veterans facility, your veterans’ benefits are your primary and only coverage. When you go to a civilian doctor or hospital, Medicare is your primary and only coverage.

By having both veterans and Medicare benefits, you get access to all civilian and non-civilian doctors and hospitals.


Is a Medicare Supplement plan primary or secondary?
Medicare Supplement plans are secondary payers to Medicare. Medicare will be billed first, then your supplement plan will be billed second.
Does Medicare send claims to your Medicare Supplement insurance?
Yes, all claims will be sent to Medicare first, then Medicare will bill the remainder to your Medicare Supplement carrier.
What is the Medicare Secondary Payer Act?
Congress passed legislation to ensure that Medicare funds are not being used to pay for services that other health insurance coverage would normally pay for as primary.
Do you need secondary insurance with Medicare?
That depends on your specific situation. Since Medicare doesn’t cover 100% of your medical services, looking into a form of secondary coverage, such as Medigap or Medicare Advantage, to help cover out-of-pocket costs you are left responsible to pay will reduce your financial obligation.
How does primary and secondary insurance work with Part D?
Part D will coordinate benefits with other prescription drug plans. Any other prescription coverage you have will determine which coverage is primary and which coverage is secondary.

How to Enroll in Secondary Insurance for Medicare

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Jagger Esch

Jagger Esch is the Medicare expert for MedicareFAQ and the founder, president, and CEO of Elite Insurance Partners and Since the inception of his first company in 2012, he has been dedicated to helping those eligible for Medicare by providing them with resources to educate themselves on all their Medicare options. He is featured in many publications as well as writes regularly for other expert columns regarding Medicare.

20 thoughts on “Is Medicare Primary or Secondary

  1. I have ben told that since I have Medicare Advantage United Health PPO Plan, Medicare is no longer my primary and is not paying anything toward my costs…Is that true ? and do I have the cheapest best plan. I live in Fla & Mass.

    1. This is true. Medicare is no longer your primary source of coverage when you enroll in a Medicare Advantage plan. In terms of lowest cost for a plan, premium is only a portion of your costs. You will need to factor out-of-pocket costs as well. For most, Medicare Supplement plans tend to save you more money in the long run. However, that does vary by your healthcare needs.

  2. I have both original Medicare and Washington state Medicaid. I had a broken and infected tooth, and learned I no longer have dental through medicaid, was handed a pamphlet and said I had to apply ” here” to have any dental benefits. ” Here” is United healthcare dual complete Plan dual snp…. It feels like a horrid, tactical error….. They would become primary over Medicare?

    1. Dana, if you enroll with UHC dual, UHC will become your primary coverage. If you wish to keep your Original Medicare, you can enroll in a stand-alone dental plan to cover these benefits

  3. Nobody ever seems to cover my situation.
    I am 64. Currently employed with group healthcare insurance. I am also disabled and receiving SSDI. As such, I am eligible for Part A and art B. I have Part A but have declined Part B. Who is Primary, Medicare or my GHP?

    PS: My GHP thinks they are secondary because I have declined Part B. The BCRC says Medicare is secondary.

    1. James, this depends on a few factors. If you are still employed by the company providing your GHP, and your company has over 100 employees, the GHP will pay primary. If your company has less than 100 employees and is not part of a multi-employer GHP, Medicare will be primary. If you are retired and receiving Part A benefits, Medicare will pay first.

  4. In addition Medicare is primary when you have Part B only or are in an individual plan. My question is if a person has Part B only, then picks up Part A at a later time, does Medicare remain primary due to the Cardinal Rule?

    1. Hi Heather – depending on the other coverage the individual has, the coordination of benefits would remain the same as before they picked up Part A. Yet, there is little reason to have Part B without Part A, since Part B involves a monthly premium and most Medicare-eligible people qualify for premium-free Part A.

      Also, Part A covers inpatient care while Part B covers outpatient care.

  5. If I’m sick for 3 days, can I use my card for emergency clinic, I heard that you need to schedule to go to your primary?

  6. If I have my son on my employer plan, and he becomes eligible for Medicare in November, which plan would be primary for him. Medicare or my employer plan insurance?

  7. If a patient has Medicare as primary and BCBS as secondary and the provider is not contracted with Medicare, do we still have to submit to Medicare first and then BCBS or can we submit to BCBS directly? Assuming Medicare will just deny the claim correct?

    1. Hi Janine. If the doctor does not accept Medicare, the secondary insurance will not cover the service either. The client is 100% responsible for the costs.

  8. I have a BCBS blue advantage hmo through the market place and was enrolled in medicare after choosing that. Currently we have tax credit, but when I report change I will become responsible for premium and they state I can keep that policy if I do so. Can my marketplace plan be the primary as it covers all the TBI injury I have and Medicare does not? If so how do I make it primary?

    1. Hi Cheryl! As soon as you become eligible for Medicare, you’ll no longer be eligible for premium subsidies through the Marketplace. Marketplace coverage and Medicare do not coordinate with one another. Your Marketplace coverage will not cover your health costs if you have Medicare. In addition, once you have Medicare and leave the Marketplace plan, you cannot get it again. So I think the information you received is incorrect. I would recommend giving us a call to figure out what you actually have and what Medicare plan will cover your TBI injury.

  9. If My last day of physically working was on 08/14/2020 and I’ve had Medicare since 08/01/2020, would Medicare become primary on 08/15/2020?

    1. Hi Kathy! I would contact your benefits administrator to confirm when Medicare becomes primary. It’s not the same for everyone.

  10. I have FEHB (federal employees health benefits)….I am a retired federal plan I am thinking of switching to is thru aetna medicare advantage plan..with that being said would medicare be primary as it is with most FEHB plans?..thanks..

    1. Hi Joe! If you enroll in Part B and keep your FEHB, then your FEHB will be primary. If you choose to enroll in a Medicare Advantage plan, you still have to pay your Part B premium, just keep that in mind. Usually, most on FEHB will go with Part A and Part B since there is not much advantage to enrolling in a Medicare Advantage plan. Medicare Advantage plans and FEHB are very alike. There isn’t much need to have both. I hope this helps!

  11. Hi Samantha. That is a great question! This is because Medicare Advantage replaces your Original Medicare benefits. Medicare is no longer responsible for your medical costs, the Advantage plan is. Medicare pays the Advantage carrier to take on your risk. That’s how the carriers are able to offer zero-premium plans.


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