The short answer: probably not, and you may not be allowed to buy it

If you have both Medicare and Medicaid, you usually do not need supplemental insurance—often called Medigap or Medigap plans. Medicaid already covers many of the costs that Medigap would pay, like copayments, coinsurance, and deductibles. In fact, most states do not let you buy Medigap if you are on Medicaid at the same time. Buying both would mean paying for overlapping coverage you cannot use.

The real question is not whether you need Medigap. It is whether your current Medicaid coverage is strong enough for your situation, and what happens to your coverage if your income or circumstances change.

Key Takeaways

  • Medicaid covers the out-of-pocket costs that Medigap is designed to pay, so having both at once creates duplicate coverage you cannot claim.
  • Most states prohibit you from buying Medigap while you are on Medicaid, though a few states have exceptions for certain situations.
  • If you lose Medicaid may be able to access, you may have a limited window to buy Medigap without waiting periods or higher premiums.
  • Your Medicaid coverage may include services Medicare does not—like long-term care or dental—so losing Medicaid could leave gaps even if you buy Medigap later.
  • Contact your state Medicaid office to confirm what your current plan covers and what your options are if your income changes.

How Medicaid and Medicare work together when you have both

When you are enrolled in both programs, Medicaid is called the "payer of last resort." This means Medicare pays first for covered services, and then Medicaid covers what Medicare does not pay. Medicaid picks up the copayments, coinsurance, and deductibles that Medicare leaves you responsible for.

Medigap plans are built to do exactly that same job—fill in Medicare's gaps. If Medicaid is already doing it, Medigap has nothing left to pay. Insurance companies know this, which is why most states have rules against selling Medigap to people on Medicaid. You would be paying a premium for a policy that cannot pay anything.

State rules on Medigap and Medicaid

The federal government allows states to decide their own Medigap rules for people on Medicaid. Most states straightforward prohibit the sale of Medigap to anyone receiving Medicaid benefits. A few states have narrow exceptions—for example, some allow Medigap purchase only for people who are both on Medicare and Medicaid but have income above a certain threshold, or only for specific Medigap plans.

Your state Medicaid office can tell you whether Medigap is available to you. You can find your state office through the Medicaid website at medicaid.gov, or call 1-800-MEDICARE to be transferred to your state's line. Have your Medicaid member ID ready when you call.

What to do if your income increases and you lose Medicaid

Medicaid may be able to access is based on income. If your income rises—through a raise, a pension increase, or other earnings—you may lose Medicaid coverage. When that happens, you lose the gap coverage Medicaid was providing, and you will have out-of-pocket costs under Medicare alone.

Federal law gives you a 63-day window after you lose Medicaid to buy Medigap without waiting periods or higher premiums based on your health history. This is called a "may provide issue" period. You do not have to answer health questions, and insurance companies cannot charge you more because of pre-existing conditions.

If you miss that 63-day window, you can still buy Medigap, but insurers may deny you or charge higher premiums. Some states have additional protections, so check with your state insurance commissioner's office if you are turned down.

Services Medicaid covers that Medigap does not

Medicaid covers some services that Medicare does not, and Medigap does not cover them either. These vary by state but often include long-term care (nursing home or home care), dental work, vision care, and hearing aids. If you lose Medicaid and buy Medigap instead, you will lose coverage for these services.

Before your income changes or you make any changes to your coverage, ask your state Medicaid office for a list of services your current plan covers. Compare that list to what Medicare and Medigap would cover. The gap between them may be significant enough that losing Medicaid is a bigger change than buying Medigap can fix.

What happens if you are on Medicare Advantage and Medicaid

Some people on Medicaid are enrolled in a Medicare Advantage plan (Part C) instead of Original Medicare. Medicare Advantage plans are run by private insurance companies and often have lower out-of-pocket costs than Original Medicare. Medigap is not sold to people on Medicare Advantage at all—regardless of whether they have Medicaid.

If you are on both Medicaid and Medicare Advantage, your Medicaid covers the copayments and coinsurance from your Advantage plan. If you lose Medicaid, you would stay in your Medicare Advantage plan but would owe those costs yourself. You cannot switch to Original Medicare and buy Medigap outside of the annual open enrollment period, unless you have a may have access to life event (like losing Medicaid).

Planning ahead if your situation might change

If you think your income might increase—through work, a bonus, an inheritance, or a change in benefits—talk to your Medicaid caseworker now. They can explain how the increase would affect your Medicaid and what your options would be. Some income does not count toward the limit, and some increases happen gradually, so the timing of when you lose coverage may be flexible.

Write down the date you lose Medicaid. Mark your calendar 63 days later. That is your important date to buy Medigap without penalties. If you wait until after that date, you may not be able to buy it at all, or you may pay much more. Some people in this situation choose to stay on Medicare Advantage instead, since it does not require Medigap and may have lower premiums.

Frequently Asked Questions

Can I buy Medigap while I am still on Medicaid, just in case I lose it later?

No. Most states prohibit insurance companies from selling Medigap to anyone currently on Medicaid. You have to wait until after you lose Medicaid to buy it. That is why the 63-day may provide issue period after you lose Medicaid is so important—it is your window to buy without health questions.

What if I am on Medicaid in one state and move to another?

Your Medicaid coverage ends when you move. You will need to explore for Medicaid in your new state, and the income limits and covered services may be different. Contact your new state's Medicaid office as soon as you move. If you lose coverage during the move, the 63-day Medigap window still applies.

Does Medicaid cover the Medicare Part B premium?

Yes. If you are on Medicaid, your state usually pays your Medicare Part B premium for you. Some states also pay Part D (prescription drug) premiums. Check with your state Medicaid office to confirm what premiums they cover, because this varies by state and by your income level.

If I buy Medigap after I lose Medicaid, will it cover everything Medicaid did?

No. Medigap covers Medicare's gaps—copayments, coinsurance, and deductibles. It does not cover services that Medicare does not cover, like long-term care, dental, or vision. If Medicaid was paying for any of those, you will lose that coverage when you switch to Medigap.

Can I switch from Medicaid to Medicare Advantage to avoid buying Medigap?

If you lose Medicaid, you can stay on Medicare Advantage or switch to Original Medicare. Medicare Advantage often has lower premiums and out-of-pocket costs than Original Medicare plus Medigap, but it has network restrictions and may not cover services outside your plan's area. Compare the plans available to you in your state before you lose Medicaid.