How Medicare Coordinates With Other Insurance: VA, TRICARE, Employer and More

What "Medicare Secondary Payer" Actually Means

Medicare Secondary Payer (MSP) is the umbrella term for the rules that decide who pays your medical bills first when you have Medicare and another type of insurance. The plan that pays first is called the primary payer. It pays up to the limits of its coverage, then hands the leftover bill to the secondary payer, which pays some or all of what the first plan did not.

These rules exist because Congress wants private and employer coverage to pay before Medicare whenever the law allows. Getting the order right protects you from denied claims, and it protects Medicare from paying bills that another insurer should have covered. The Medicare Secondary Payer Questionnaire (MSPQ), which we cover later, is the tool providers use at check-in to sort this out.

In 2026, the standard Medicare Part B premium is $202.90 per month, up from $185 in 2025, and the annual Part B deductible is $283, up from $257. Those numbers matter here, because being wrong about who pays primary can leave you exposed to the full 20% of Part B services plus that deductible on every visit.

Medicare and Employer Group Health Plans (Size Matters)

If you or your spouse are still actively working and covered by a job-based plan, the employer's size decides who pays first.

For beneficiaries age 65+ whose coverage is based on their own or a spouse's current employment, an employer with 20 or more employees pays primary and Medicare pays secondary. If the employer has fewer than 20 employees, Medicare pays primary and the group plan pays secondary. For disability-based Medicare, the threshold flips to 100 employees, and for End-Stage Renal Disease (ESRD), the group health plan is generally primary for the first 30 months of Medicare eligibility regardless of employer size.

One nuance to know: employer size is based on the number of employees, not the number of people covered under the plan. And in multi-employer arrangements, if any one participating employer has 20+ employees, the age-based MSP rules generally apply across the arrangement.

Do you need Part B if you have an active employer plan?

If your employer has 20+ employees and you have solid coverage, you can usually delay Part B without penalty and enroll during a Special Enrollment Period when you retire. If your employer has fewer than 20 employees, Medicare is primary, so you almost certainly need Part B or you will have huge gaps. For a deeper look at this decision, see our guide on working past 65. Confirm in writing with your HR department before delaying.

Retiree Coverage and COBRA

Once you stop actively working, the rules change. Retiree health benefits and COBRA are not considered "current employment" coverage, so Medicare moves to the front of the line.

• Retiree plans: Medicare is primary, retiree plan is secondary.
• COBRA: Medicare is primary, COBRA is secondary (with a narrow ESRD exception during the 30-month coordination period, when COBRA pays first).

Because Medicare pays first, you generally must enroll in Part B when you first become eligible, even if you plan to keep retiree coverage or elect COBRA. If you skip Part B, the retiree or COBRA plan may only pay the small share Medicare would have left, leaving you exposed. You could also face a lifelong Part B late-enrollment penalty. To see the real dollar impact of that penalty, review our late enrollment penalty guide.

VA Benefits and Medicare Do Not Coordinate

This is one of the most misunderstood areas in Medicare. VA health care and Medicare are two completely separate systems. They do not act as a primary/secondary pair on the same bill. You choose which system to use for each episode of care.

• Use VA for care at VA facilities or VA-authorized community care.
• Use Medicare for care at non-VA doctors, hospitals, and outpatient centers.
• The VA will not bill Medicare, and Medicare will not reimburse the VA for services it provides.

Do veterans need Part B?

Legally, no. VA benefits alone do not require Part B. But VA health care is not considered creditable coverage for Medicare Part B, so if you skip Part B and enroll later, you can owe a permanent 10% premium penalty for every 12 months you could have had it. If you rely only on VA and later want to see civilian doctors, or the VA changes your priority group, that penalty compounds fast. For example, a 10-year delay would equal a 120% surcharge added to your monthly Part B premium for the rest of your Medicare life. Most veterans enroll in Part B for flexibility, then decide whether to add a Medigap or Medicare Advantage plan on top.

TRICARE for Life for Military Retirees

TRICARE for Life (TFL) is the military retiree benefit that acts like a wraparound. Unlike VA, it does coordinate with Medicare, but only under one strict condition: you must be enrolled in both Medicare Part A and Part B.

TFL coverage automatically begins the first day that you have both Medicare Parts A and B. There are no TFL enrollment forms or enrollment fees. For coordination, Medicare pays first for services it covers, and TFL pays second, typically covering the remaining Medicare cost-sharing.

Once you are entitled to Medicare Part A, you must enroll in and pay for Medicare Part B to keep your TRICARE coverage, which then acts as a second payer to cover your remaining out-of-pocket costs. Drop Part B, and you lose TFL. In 2026, that means the $202.90 monthly Part B premium is effectively your only cost to maintain TFL coverage.

For military families, this makes Part B non-negotiable at age 65. The good news is that many retirees find TFL plus Medicare eliminates the need for a separate Medigap plan, because TFL already fills in the 20% Part B gap. Learn more if you are also weighing Medicare Advantage vs Medigap as an alternative.

FEHB and the New PSHB Program for Federal Retirees

Federal Employees Health Benefits (FEHB) is one of the richest retiree health programs in the country. In 2025, a big change kicked in for postal workers: the Postal Service Health Benefits (PSHB) program replaced FEHB for USPS retirees and eligible family members.

• Retired federal employees with FEHB and Medicare: Medicare is primary, FEHB is secondary.
• Actively working federal employees: FEHB is primary, Medicare is secondary if you enroll.
• FEHB does not require Part B. OPM states there is no Medicare Part B enrollment requirement in the FEHB Program; the Part B mandate applies to PSHB (Postal) annuitants, not to FEHB.
• PSHB (Postal) retirees: Most Medicare-eligible postal retirees are now required to enroll in Medicare Part B to keep their PSHB coverage.

For PSHB, exceptions exist for retirees who retired on or before January 1, 2025 and were not already enrolled in Part B, people living outside the United States, and certain enrollees eligible for VA or Indian Health Service benefits.

When Medicare is primary and FEHB is secondary, many FEHB plans waive deductibles, copays, and coinsurance, which can dramatically reduce out-of-pocket costs. Some FEHB plans now also bundle a Medicare Advantage or Part D benefit for enrollees who take Medicare.

Workers' Compensation, Liability, and No-Fault

Anything work-related, or covered by auto or liability insurance, is handled outside the normal MSP flow.

• Workers' compensation is primary for work-related injuries or illnesses. Medicare will not pay for care that workers' comp is responsible for.
• Auto/liability and no-fault insurance is primary for accident-related care up to policy limits.
• Providers bill the primary insurer first, and Medicare only steps in for approved secondary amounts (or as a conditional payment if the primary is slow to pay).

Indian Health Service (IHS)

For Medicare beneficiaries who use Indian Health Service, urban Indian organizations, or Tribal 638 facilities, IHS is not treated as private insurance. IHS is considered the payer of last resort, so Medicare generally pays first for services at Medicare-participating facilities. IHS then covers eligible remaining amounts based on facility rules. Enrolling in Part B is strongly encouraged so that Medicare can pay its share and preserve IHS resources for other tribal members.

The Medicare Secondary Payer Questionnaire (MSPQ)

Every time you check in for Medicare-covered services, the provider is expected to ask a set of questions to figure out if Medicare is really primary. That form is the MSPQ. Typical MSPQ questions include:

1. Are you currently employed, or is your spouse?
2. Is the visit related to a work injury or illness?
3. Is the visit related to an auto accident or other liability?
4. Do you have black lung benefits or veterans' benefits?
5. Do you have coverage through a family member's group health plan?

Answering honestly and consistently keeps your claims moving. Wrong answers, even accidental ones, can trigger denials months later.

How to Avoid Gaps and Duplicate Premiums

The biggest coordination mistakes fall into two buckets: gaps (skipping Part B when you needed it) and duplicates (paying for coverage that overlaps).

• Do not pay for Medigap and FEHB or TFL at the same time. They largely cover the same gaps.
• Do not enroll in a Medicare Advantage plan while keeping VA as your only backup unless you understand how the networks interact.
• Enroll in Part B on time when you have retiree, COBRA, TRICARE for Life, or PSHB (or FEHB if you want secondary payment to kick in fully).
• Notify every plan when you enroll in Medicare so claims route correctly.

If you decide a supplement makes sense, compare Medicare Supplement Plan G and lower-premium alternatives like Plan N before enrolling. Quotes for the same lettered plan can vary by hundreds of dollars per year between carriers. If you are pairing Medigap with drug coverage, see our Medigap and Part D guide. And if you are just starting the process, our step-by-step enrollment guide walks through every deadline.

Frequently Asked Questions

Can I have Medicare and VA benefits at the same time?

Yes, and many veterans do. However, VA and Medicare do not coordinate benefits, so you choose which system to use for each visit. Most veterans enroll in Part B for flexibility, because VA coverage is not considered creditable for the Part B late-enrollment penalty and delaying could cost you 10% per year for life.

Do I need Medicare Part B if I have TRICARE for Life?

Yes. TRICARE for Life eligibility requires you to have both Medicare Part A and Part B. If you drop Part B or skip enrolling at 65, you lose TFL coverage. In 2026, the $202.90 monthly Part B premium is your only ongoing cost to maintain TFL, which then acts as your secondary payer wrapping around Medicare's cost-sharing.

Is Medicare primary if I have COBRA?

Yes, almost always. Because COBRA is not based on current employment, Medicare pays first and COBRA pays second. The main exception is during the first 30 months of Medicare eligibility based on End-Stage Renal Disease, when COBRA pays first. COBRA also does not give you an 8-month Special Enrollment Period for Part B, so enrolling on time matters.

Do federal retirees need Medicare Part B if they have FEHB or PSHB?

For FEHB, no. Most civilian federal retirees can keep FEHB without enrolling in Part B, though many still opt in because Medicare pays first and FEHB fills in the gaps. For PSHB (postal retirees), Part B is generally required to keep coverage, with limited exceptions for those who retired on or before January 1, 2025, live overseas, or are eligible for VA or IHS benefits.

What is the Medicare Secondary Payer Questionnaire?

The MSPQ is a short form providers use at check-in to determine whether Medicare should be billed as primary or secondary. It asks about current employment, work injuries, auto accidents, and other coverage. Answering carefully helps prevent denied claims and later bill-backs from CMS.