The short answer
Medicare pays first and COBRA pays after it, unless you have End-Stage Renal Disease. The order you took them in decides what else happens. If you had COBRA before signing up for Medicare, Medicare states your COBRA will probably end once you sign up.
You are holding two cards. One says Medicare and one is the employer plan you kept after the job ended. A hospital is about to bill one of them first, and which one is not decided by either card. It was decided by the order you got them in.
Is COBRA or Medicare primary?
Medicare is primary. Medicare states it in one sentence, and the sentence carries its own exception: COBRA pays after Medicare, unless you have End-Stage Renal Disease. So the employer plan, continued under COBRA, is the one that pays second.
COBRA is the law that lets that plan continue. Medicare describes it as a federal law that may let you keep your employer group health plan coverage for a limited time after your employment ends, or if you lose coverage as a spouse or dependent of the covered employee.
Who can hold it is wider than the employee. Medicare's description reaches a spouse or a dependent of the covered employee who loses coverage, so the two cards can end up with someone who never held the job the plan came from.
The exception belongs to the page on Medicare with kidney failure, which carries what End-Stage Renal Disease changes and why.
Should I take COBRA instead of Medicare?
Instead is the word that causes damage, because Medicare treats the two as stacked rather than as alternatives. It states that if you have COBRA and are eligible for Medicare but not enrolled, COBRA may only pay a small portion of the health care services you get.
Medicare finishes that sentence with the consequence: you may have to pay most of the costs yourself.
Read the condition in that sentence carefully. It is not a statement about COBRA. It is a statement about being eligible for Medicare and not enrolled, which is a state you can be in while holding a COBRA card and believing you are covered.
Medicare's own instruction for that state is to contact your COBRA plan and ask what percent they pay.
Here is what this page will not tell you, and the reason. Neither government page linked below states what COBRA costs, what share it pays, or what percentage to expect. Medicare answers the cost question by telling you to go and ask your own plan. No figure is supplied here in place of one the government does not publish.
Does COBRA delay my Part B penalty?
No. Medicare states it directly: COBRA coverage does not extend your limited time to sign up for Medicare. Taking COBRA changes what you are insured by and changes nothing about the deadline. The clock was started by the job ending, and it keeps running underneath the new card.
What you count from is the job, not the COBRA. Medicare states the window runs up to eight months after you stop working, or after you lose your health insurance if that happens first, whether or not you choose COBRA.
That last clause is the whole answer to this heading. The deadline does not know which card is in your wallet.
How that window is counted, what happens if you miss it, and how the penalty is worked out all belong to other pages: can I delay Medicare Part B if I am still working, the Medicare general enrollment period, and the Medicare Part B late enrollment penalty.
What happens if I have both?
That depends on which one you had first, and Medicare gives two different answers. It puts them in two drawers under one heading and never says what they mean together. Read side by side, they show that of the two orders, just one makes holding both the likely outcome.
| Which one came first | What Medicare says happens | The trap |
|---|---|---|
| COBRA, then Medicare | Your COBRA will probably end once you sign up | You may not end up with two payers |
| Medicare, then COBRA | COBRA pays after Medicare | The exception is End-Stage Renal Disease |
The top row is the one that changes a plan. It describes signing up for Medicare while holding COBRA, and the expected result is a queue: Medicare in front, the old plan behind it filling gaps. Medicare says the old plan will probably stop instead.
That word is Medicare's and it is worth keeping. It says probably, not certainly, and it names no condition that decides which way it goes. So the honest version is that you cannot plan on keeping it, and your COBRA plan is the party to ask what yours will do.
The bottom row is the queue itself, and it is the one you reach by taking Medicare first.
How long does COBRA last with Medicare?
Not indefinitely, and the limit belongs to COBRA rather than to Medicare. COBRA coverage is generally offered for 18 months, and for 36 months in some cases. Medicare directs questions about your own COBRA rights to your employer's benefits administrator or group health plan.
Whether it is available at all turns on the size of the employer. In general COBRA only applies to employers with 20 or more employees.
Some states close part of that gap. Medicare states that some states have mini-COBRA laws requiring insurers covering employers with fewer than 20 employees to let you keep coverage for a limited time, and it says to check with your state insurance commissioner's office. It names no states, and neither does this page.
Getting COBRA at all runs through a chain of notices rather than an application you file. Medicare states that your employer must tell the plan administrator why you qualify, and that once the plan administrator is notified, the plan must let you know you have the right to choose COBRA coverage.
So two other parties act before you do. If the group health plan coverage has ended and no notice arrives, Medicare directs the question to your employer's benefits administrator or the plan itself.
One ending is not about time at all. If the former employer goes bankrupt or out of business and there is no longer a health plan, Medicare states there is no COBRA coverage available. In that case you may have the right to buy a Medicare Supplement Insurance policy even outside the usual window, which the page on the Medigap open enrollment period covers.
What is the costly mistake people make?
The expensive position is a state rather than an event: eligible for Medicare, holding COBRA, and not enrolled. Medicare attaches its warning to exactly that combination, and it is reachable by someone who did everything their employer told them to do.
From inside it, nothing looks wrong. The card works. The premium leaves the account. The plan is the same one it was, and what changed is a birthday rather than the plan.
What changed underneath is which payer is supposed to be in front. Medicare states that if you have COBRA and are eligible for Medicare but not enrolled, COBRA may only pay a small portion of the services you get, and that you may have to pay most of the costs yourself.
The second cost runs alongside the first, because the eight month deadline is keyed to the job and is unaffected by any of this.
Medicare's own instruction for that position is about timing rather than about COBRA. It says to sign up for Medicare when you turn 65 to avoid gaps in coverage and a monthly Part B late enrollment penalty, and separately not to wait until COBRA ends before taking Part B.
Both halves of that instruction point at the same thing. Nothing about holding COBRA moves the date the instruction is keyed to.
What this means for you
Answer one question before the others: which came first. If Medicare came first, COBRA pays after it and you hold both. If COBRA came first, Medicare states your COBRA will probably end when you sign up, so treat keeping it as something to confirm rather than assume.
For a household the trap is not choosing wrongly between them. It is being eligible, insured by COBRA, and unenrolled, which reads as covered from the inside and pays like neither.
FAQ
Which one pays first, COBRA or Medicare?
Medicare pays first. Medicare states the rule in a single sentence that carries its own exception: COBRA pays after Medicare, unless you have End-Stage Renal Disease. COBRA is the federal law that lets employer group health plan coverage continue for a limited time after employment ends, or after you lose coverage as a spouse or dependent of the covered employee.
So the plan continuing under COBRA is the same plan it always was. Its position is not, and nothing printed on the card records the change. Medicare directs questions about how your own COBRA works alongside Medicare to the Benefits Coordination and Recovery Center.
Will my COBRA stop if I sign up for Medicare?
Medicare says it probably will. Its guidance for someone who has COBRA and has not yet signed up is that your COBRA coverage will probably end once you sign up, and that you should not wait until COBRA ends to take Part B, because COBRA does not extend your limited time to sign up.
The word probably is Medicare's own and it names no condition that settles which way any particular plan goes. So the safe reading is that you cannot plan on keeping COBRA as a supplement after enrolling, and that your COBRA plan or the employer's benefits administrator is where to ask what yours will do.
How long does COBRA last, and does everyone get it?
COBRA coverage is generally offered for 18 months, and for 36 months in some cases. Availability depends on the size of the employer rather than on your own situation: in general COBRA only applies to employers with 20 or more employees.
Some states narrow that gap with mini-COBRA laws requiring insurers covering employers with fewer than 20 employees to let you keep coverage for a limited time. Medicare does not name which states those are, and neither does this page.
It directs you to your state insurance commissioner's office to find out whether coverage is available to you, and to your employer's benefits administrator for your own COBRA rights.
What does COBRA actually pay once I am eligible for Medicare?
Medicare attaches its answer to a specific condition, and the condition is the whole point. If you have COBRA and you are eligible for Medicare but not enrolled, COBRA may only pay for a small portion of the health care services you get, and you may have to pay most of the costs yourself.
That warning is about being eligible and unenrolled rather than about COBRA in general. Medicare does not publish what the small portion is, what share any plan pays, or a percentage to expect.
Its instruction is to contact your COBRA plan and ask what percent they pay, and no figure is offered here in place of one the government does not state.
What if my old employer goes out of business?
Then the answer stops depending on COBRA's usual rules. Medicare states that if there is no longer a health plan, there is no COBRA coverage available at all, though federal COBRA rules may still protect you and another plan offered by the company may cover you instead.
Union members covered by a collective bargaining agreement that provides a medical plan may also have continued coverage. There is one route that opens if none of those work.
Medicare states that if you cannot get COBRA continuation coverage, you may have the right to buy a Medicare Supplement Insurance policy even when you are no longer in your Medigap open enrollment period.
Who can answer a question about my own COBRA and Medicare?
Medicare names four routes and they answer different questions. Your employer's benefits administrator handles questions about your specific COBRA options. For how COBRA affects Part B or a Medigap policy, Medicare directs you to your State Health Insurance Assistance Program.
For COBRA and Medicare together, it names the Benefits Coordination and Recovery Center on 1-855-798-2627, with a text telephone line on 1-855-797-2627.
For questions about the group health plan itself, it splits by employer type: the Department of Labor for a private employer, the Centers for Medicare and Medicaid Services for a state or local government employer, and the Office of Personnel Management for the federal government.
