Medicare is always the primary payer when you have both Medicare and Medicaid. Medicaid never pays first for any service that Medicare covers. Instead, Medicaid acts as secondary insurance, picking up some or all of the remaining costs after Medicare has paid its share.
How the Two Programs Work Together
People who qualify for both Medicare and Medicaid are called “dually eligible.” About 12 million Americans fall into this category, typically because they’re 65 or older (or have a qualifying disability) and also have limited income. For these individuals, the payment process follows a strict order: Medicare processes the claim first and pays up to its coverage limits. Then Medicaid reviews what’s left, including deductibles, coinsurance, and copays, and may cover part or all of those remaining costs depending on the state.
This process happens largely automatically through what’s called the “crossover” system. After Medicare processes a claim, it electronically forwards the claim details to the state Medicaid agency or Medicaid managed care plan. You generally don’t need to submit separate claims yourself.
What Medicaid Covers That Medicare Doesn’t
The primary/secondary distinction only applies to services Medicare covers. For services Medicare doesn’t cover at all, Medicaid steps in as the sole payer. The biggest example is long-term care. Medicare generally doesn’t pay for ongoing nursing home stays or help with daily activities like bathing and dressing. Medicaid is the main program that covers long-term custodial care for people with limited income and resources, and most nursing homes accept Medicaid payment.
Medicaid also covers services in many states that Medicare skips entirely, such as dental care, vision, hearing aids, and personal care services. For these, there’s no coordination question because only one program is involved.
How Prescription Drugs Are Handled
If you’re dually eligible, Medicare covers your prescription drugs, not Medicaid. You’ll be automatically enrolled in a Medicare Part D drug plan, and you’ll also automatically receive Extra Help, a federal program that significantly reduces your drug costs, including premiums, deductibles, and copays.
There’s one exception worth knowing: if Medicare doesn’t cover a particular prescription, Medicaid may still cover it depending on your state’s formulary. This can matter for certain medications that fall outside Part D’s scope.
Protection From Out-of-Pocket Costs
Dual eligibility comes with strong billing protections, especially for people in the Qualified Medicare Beneficiary (QMB) program. Federal law prohibits Medicare providers and suppliers, including pharmacies, from billing QMBs for any Medicare cost-sharing. That means no deductibles, no coinsurance, and no copays for Medicare-covered services. This applies to both in-network and out-of-network providers.
Non-participating Medicare doctors, who normally can “balance bill” patients for charges above the Medicare-approved amount, lose that ability with dually eligible patients. They must accept the Medicare-approved amount as the basis for payment. If Medicaid pays some or all of the remaining cost-sharing, the provider must accept that as payment in full.
One group that doesn’t get full protection: partial-benefit dually eligible individuals whose only Medicaid benefit is coverage of Medicare premiums. If you’re not in the QMB group, you may still owe Medicare cost-sharing amounts.
Medicare Savings Programs
Several Medicaid programs exist specifically to help pay your Medicare costs. These don’t change which program is primary, but they reduce or eliminate what you owe.
- QMB Program: Pays your Medicare Part A and Part B premiums plus all cost-sharing. For 2026, the income limit is $1,350 per month for individuals or $1,824 for married couples, with a resource limit of $9,950 (individual) or $14,910 (couple).
- SLMB Program: Pays your Part B premium only. Income limit of $1,616 per month for individuals, $2,184 for couples, with the same resource limits.
- QI Program: Also pays your Part B premium. Income limit of $1,816 per month for individuals, $2,455 for couples.
These limits are slightly higher in Alaska and Hawaii, and some states use more generous thresholds than the federal minimums.
Dual Eligible Special Needs Plans
If you have both Medicare and Medicaid, you may be able to join a Dual Eligible Special Needs Plan (D-SNP). These are Medicare Advantage plans designed specifically to coordinate your benefits across both programs. They cover everything standard Medicare Advantage plans cover, including Part D drug coverage, but they may also offer extra benefits tailored to people with complex health needs, such as additional hospital days for serious conditions.
D-SNPs are structured as HMO or PPO plans and include built-in care coordination services. The advantage over regular Medicare is that one plan manages both your Medicare and Medicaid benefits, reducing the confusion of dealing with two separate programs.
CMS is pushing these plans toward deeper integration. Starting in 2027, in areas where the same parent company runs both a D-SNP and a Medicaid managed care plan, new D-SNP enrollees will need to also be enrolled in the affiliated Medicaid plan. By 2030, all members of those D-SNPs must be enrolled in the linked Medicaid plan. The goal is to create a more seamless experience where one organization handles everything. Full-benefit dually eligible individuals also now have a monthly special enrollment period to switch into an integrated D-SNP at any time, giving more flexibility than standard Medicare enrollment windows allow.