Switching from Medicaid to Medicare isn’t always a full switch. Most people who become eligible for Medicare can keep Medicaid too, becoming what’s known as “dual eligible.” The key is signing up for Medicare on time and understanding how the two programs work together so you don’t end up with gaps in coverage or unexpected costs.
Why the Switch Happens
Medicare eligibility kicks in under three circumstances: you turn 65, you’ve received Social Security Disability Insurance (SSDI) benefits for 24 months, or you have end-stage renal disease. If you’ve been on Medicaid and one of these applies to you, Medicare becomes your primary insurance. That means Medicare pays first for hospital stays, doctor visits, and other medical services. Medicaid drops to a secondary role, picking up costs that Medicare doesn’t cover.
This isn’t optional. Once you’re Medicare-eligible, Medicaid expects you to enroll. If you don’t, your state Medicaid program may reduce or end certain benefits because it assumes Medicare should be covering them.
You May Not Have to Give Up Medicaid
Many people keep both programs. Dual-eligible beneficiaries get Medicare for acute care (doctor visits, hospital stays, outpatient services) while Medicaid continues to help with premiums, copays, and services Medicare doesn’t cover, like long-term care, personal care aides, dental, and vision. Medicaid never pays before Medicare. It fills in the gaps after Medicare and any supplemental insurance have paid their share.
Whether you stay on Medicaid depends on your state’s income and asset rules. Your eligibility gets reassessed, and if your income is still low enough, you remain enrolled in both. Contact your state Medicaid office to confirm your status once you begin the Medicare enrollment process.
The Enrollment Timeline
If you’re turning 65, your Initial Enrollment Period lasts seven months: it starts three months before your birthday month and ends three months after it. You can sign up for Medicare Parts A and B online through the Social Security Administration at ssa.gov, by calling 800-772-1213, or by visiting a local Social Security office.
If you’re already receiving Social Security retirement benefits, you’ll be enrolled in Medicare Part A automatically when you turn 65. You’ll get your Medicare card in the mail about three months before your birthday. Part B enrollment may also be automatic, but check your paperwork carefully to confirm.
If you qualify through SSDI, Medicare starts automatically after your 24-month waiting period. For end-stage renal disease, you need to call Social Security directly at 800-772-1213 to apply.
What Happens If You Miss the Deadline
Missing your Initial Enrollment Period has real consequences. You’d have to wait for the next General Enrollment Period (January through March each year, with coverage starting in July), and you’ll face a late enrollment penalty on your Part B premium. That penalty increases the longer you go without signing up, and you pay it for as long as you have Part B coverage. If your Medicaid coverage ended on or after January 1, 2023, you get a Special Enrollment Period that lasts six months from the date your Medicaid ends. Missing that window also pushes you to the General Enrollment Period with potential penalties.
How to Handle Prescription Drug Coverage
On Medicaid, your prescriptions are covered directly. Once you move to Medicare, drug coverage shifts to a separate Medicare Part D plan. This is one of the trickiest parts of the transition because the formulary (the list of covered drugs) will likely be different. Medications you currently take may not be covered under your new Part D plan, or they may require prior authorization.
The good news: if you have full Medicaid coverage, you automatically qualify for “Extra Help,” a program that pays most of your Part D costs, including premiums, deductibles, and copays. You’ll receive a notice in the mail telling you which Part D plan you’ve been enrolled in and how much you’ll pay. If you don’t like the plan you’re assigned, you can switch. Starting in 2025, people with Medicaid or Extra Help can change their drug plan once per month, giving you flexibility to find one that covers your medications. You also won’t pay a late enrollment penalty for Part D while you’re receiving Extra Help.
Before your Medicare coverage starts, make a list of every medication you take and check whether your assigned Part D plan covers them. The Medicare Plan Finder tool at medicare.gov lets you search by drug name.
Medicare Savings Programs for Low-Income Enrollees
If your income is low but you’re not sure you’ll keep full Medicaid, Medicare Savings Programs can cover some or all of your Medicare costs. There are three tiers, each with different income limits for 2026:
- Qualified Medicare Beneficiary (QMB): Covers your Part A and Part B premiums, deductibles, copays, and coinsurance. Individual income limit is $1,350 per month with up to $9,950 in resources. For married couples, the limits are $1,824 per month and $14,910 in resources.
- Specified Low-Income Medicare Beneficiary (SLMB): Covers your Part B premium only. Individual income limit is $1,616 per month. Married couples qualify up to $2,184 per month. Same resource limits as QMB.
- Qualifying Individual (QI): Also covers Part B premiums. Individual income limit is $1,816 per month; $2,455 for married couples. Same resource limits.
Limits are slightly higher in Alaska and Hawaii, and some states allow higher thresholds than the federal minimums. You apply through your state Medicaid office, not through Medicare.
Moving From Medicaid Managed Care to Medicare Advantage
If you’re currently in a Medicaid managed care plan (an HMO or similar plan), you have options for how your Medicare coverage is structured. You can enroll in Original Medicare (Parts A and B) and keep Medicaid as a supplement. Or you can join a Medicare Advantage plan, which bundles hospital, medical, and often drug coverage into one plan.
For dual-eligible beneficiaries, Dual Special Needs Plans (D-SNPs) are specifically designed to coordinate Medicare and Medicaid benefits in a single plan. Some states have programs that let you stay with your current Medicaid managed care company by enrolling in that company’s D-SNP product. In New York, for example, a process called “default enrollment” automatically moves Medicaid managed care members into their health plan’s D-SNP when they become Medicare eligible. You keep the same plan, the same network, and get both Medicaid and Medicare services through one card.
If your state or plan offers this kind of integrated option, you’ll typically get a notice explaining the transition. You’re not locked in. You can choose a different D-SNP or opt for Original Medicare instead. Contact your current Medicaid plan or your state’s enrollment helpline to find out what integrated options are available where you live.
Steps to Take Before Your Medicare Start Date
Start preparing at least three to four months before you expect to become Medicare-eligible. If you’re turning 65, that means taking action around your 62nd birthday month at the latest for planning, and beginning the enrollment process three months before you turn 65. Here’s what to prioritize:
- Confirm your Medicare start date by contacting Social Security online or by phone at 800-772-1213.
- Contact your state Medicaid office to ask whether you’ll remain eligible for Medicaid after Medicare begins. Ask specifically about dual-eligible status.
- Review your current medications and check Part D plan formularies using the Medicare Plan Finder at medicare.gov.
- Ask your Medicaid managed care plan whether they offer a D-SNP or integrated plan for dual-eligible members.
- Apply for a Medicare Savings Program through your state Medicaid office if your income and resources fall within the limits.
Keep copies of every notice you receive from Medicaid, Medicare, and Social Security during the transition. If there’s a billing dispute or coverage gap, these documents are your proof of enrollment dates and eligibility.