Medicare and retiree health coverage: who pays first

Medicare and retiree health coverage usually work with Medicare paying first. You generally need to enroll in Part A and Part B when first eligible, even with retiree coverage. Check the plan's drug notice to see whether it is creditable for Part D.

Key facts
Who pays first	Medicare generallyRetiree coverage is not based on current employment.
Should you enroll?	Usually at 65A delay can create a Part B penalty and disrupt the retiree plan.
Drug coverage	Check creditable statusA retiree drug plan may or may not be creditable for Part D.
Retiree plan role	Usually secondaryIt may cover some costs Medicare leaves behind.
Medigap	Separate decisionA retiree plan is not the same as a Medigap policy.
Plan rules	Vary by employerSome plans require Medicare enrollment to pay benefits.

How retiree coverage fits with Medicare

Retiree health coverage is coverage from a former employer or a union. It is not based on current employment. That distinction matters because it changes how the plan works with Medicare.

When a person has retiree coverage and Medicare, Medicare generally pays first. The retiree plan generally pays second. The retiree plan may cover some of the deductible, coinsurance, or services that Medicare does not cover, depending on the plan design.

That order is different from active employer coverage. A plan based on current employment from an employer with 20 or more employees can pay first for a worker who is 65 or older. Retiree coverage does not get that treatment.

A person who is about to retire should ask the employer how the plan coordinates with Medicare. The answer should be in the plan documents, not just in a verbal summary.

Why enrolling on time matters

A person with retiree coverage should usually enroll in Part A and Part B when first eligible. Delaying Part B can create a permanent late enrollment penalty. It can also cause the retiree plan to reduce or deny benefits.

Some retiree plans require the person to enroll in Medicare as a condition of receiving retiree benefits. The plan may pay secondary benefits only if Medicare is in place. A person who delays can lose the very coverage they were trying to keep.

A person who is still working and covered by a current employer plan may have a special enrollment period later. Retiree coverage generally does not create that same protection. The person should check the specific rules before delaying.

A person who is 65 and has retiree coverage should compare the total cost of Medicare plus the retiree plan with the cost of Medicare plus other coverage. The retiree plan may be generous or may be limited. The premium and the benefits both matter.

Drug coverage and Part D

Retiree plans often include prescription drug coverage. That coverage may be creditable for Part D, meaning it is at least as good as standard Medicare drug coverage. It may also be non-creditable. The plan must tell the person each year.

If the retiree drug coverage is creditable, the person may be able to delay Part D without a penalty. If it is not creditable, the person may owe a Part D late enrollment penalty later. The penalty is generally 1 percent of the national base beneficiary premium for each full month without creditable coverage.

A person who keeps the retiree drug plan and later enrolls in Part D should ask how the two plans coordinate. In most cases, a person would not use both as primary drug coverage, but the rules and costs should be checked.

A person who loses retiree drug coverage may have a special enrollment period for Part D. The notice and the dates matter. The person should keep the creditable coverage notice.

Retiree coverage and Medigap

Retiree coverage is not Medigap. Medigap is a policy a person buys to help pay Medicare's cost-sharing. A retiree plan may work like supplemental coverage, but it is governed by the employer's plan rules, not by Medigap rules.

A person who has retiree coverage may still want to compare Medigap. The retiree plan may change benefits, raise premiums, or end coverage. Medigap policies are standardized in most states, although the rules and prices vary.

A person who is considering Medigap should check the Medigap open enrollment period. It is generally tied to the start of Part B. A delay can make it harder or more expensive to buy a policy later.

A person who keeps retiree coverage as secondary coverage should confirm that the plan pays secondary to Medicare. Some plans coordinate differently, and some reduce benefits if Medicare is not in place. A written answer from the plan is the safest record. Keep the reply with your plan documents.

Cost and plan changes

Retiree coverage can be a valuable benefit, but it is not always free. Premiums, deductibles, and copays can change. Employers can also change or end retiree plans. A person should not assume the coverage will stay the same for life.

A person who relies on retiree coverage should keep the plan documents and the annual notices. The notices explain changes, creditable drug coverage, and coordination rules.

A person who is deciding whether to keep retiree coverage should compare the total cost. Medicare Part B has a premium, and the retiree plan may have its own premium. A Medigap policy or a Part D plan may cost less or more, depending on the person's needs.

A person who drops retiree coverage may not be able to get it back. That is a reason to compare carefully before making a change. The employer's human resources office can explain the rules.

Before enrolling, ask the retiree plan four questions. Does the plan require Medicare Part B? Does it pay secondary to Medicare? Is the drug coverage creditable for Part D? Can the plan change or end the benefit? The answers should be in writing. A verbal answer is not enough if a claim is denied later.

Worked example

Suppose a person retires at 65 with retiree coverage from a former employer. The plan pays secondary to Medicare and requires the person to enroll in Part B. The person enrolls during the initial enrollment period.

The person pays the Part B premium and the retiree plan premium. The retiree plan helps with some of the costs Medicare leaves behind. The person also checks whether the retiree drug coverage is creditable.

A second person in the same situation delays Part B to save the premium. The retiree plan later reduces benefits because Medicare is not in place. The person also faces a Part B penalty when enrolling later. The short-term savings turn into a long-term cost.

A third person compares the retiree plan with a Medigap policy and a Part D plan. The total cost is similar, but the Medigap policy offers more predictable copays. The person chooses based on the doctors, drugs, and budget.

The example shows that retiree coverage is one option, not an automatic answer. The plan rules and the person's health needs should drive the decision.

Three honest caveats

Retiree coverage generally pays second to Medicare. It usually does not allow a penalty-free delay of Part B.
The plan may require Medicare enrollment to pay benefits. Read the plan documents.
Retiree drug coverage is not automatically creditable for Part D. Check the annual notice.

Frequently asked questions

Does Medicare pay first with retiree coverage?

Generally yes. Retiree coverage is not based on current employment, so Medicare usually pays first.

Can I delay Part B if I have retiree coverage?

Generally no, not without a penalty. Retiree coverage usually does not qualify for the same delay as current employer coverage.

Is retiree drug coverage creditable for Part D?

It may or may not be. The plan must tell you each year. If it is not creditable, a Part D penalty may apply later.

Is retiree coverage the same as Medigap?

No. Retiree coverage is an employer plan. Medigap is a separate policy that helps pay Medicare cost-sharing.

Can my former employer change my retiree coverage?

Employers can change or end retiree plans under the plan rules. Read the annual notices and keep the documents.

What should I do when I turn 65?

Usually enroll in Part A and Part B, then check how the retiree plan coordinates and whether its drug coverage is creditable.

Source table

Figure	Value used	Official source
Who pays first	Medicare generally	Medicare.gov who pays firstChecked October 28, 2026
Working past 65	Current employment rules	Medicare.gov working past 65Checked October 28, 2026
Part D costs and penalties	Creditable coverage rules	Medicare.gov Part D costsChecked October 28, 2026
Medicare costs	Premiums and cost-sharing	Medicare.gov costsChecked October 28, 2026

What to do next

Read the retiree plan documents before you turn 65. Confirm the coordination rules, the drug coverage notice, and whether the plan requires Medicare enrollment. The Medicare initial enrollment period guide explains the timing, and the Medicare and COBRA guide covers a related coverage type. If you are comparing paths, the Medicare vs ACA decision tool walks through the employer rules.

Medicare and retiree health coverage