Medicare Supplement Eligibility: Who Can Buy a Medigap Policy

Reviewed by Russell Noga, Licensed Medicare Insurance Broker (all 50 states) — Last updated November 8, 2026

Most people assume Medicare Supplement eligibility is about age. It’s really about which parts of Medicare you hold and what other coverage sits next to it. A 72-year-old in a Medicare Advantage plan can’t buy one today, while a 45-year-old on disability may qualify, depending on her state.

Below are the rules that decide whether you’re allowed to buy a Medigap policy at all, the situations that block a sale, and why being eligible is not the same as being accepted. A checklist and a situation-by-situation table sit near the end.

Insurers check the same basic facts on every Medigap application. If any one of them is missing, the company can’t issue the policy, no matter how healthy you are or how much you’re willing to pay.

Notice what isn’t on the list: income, assets, citizenship beyond what Medicare itself requires, or a minimum time on Medicare. Health only matters for acceptance and price, which is covered further down.

Many people who keep working past 65 take premium-free Part A and hold off on Part B while a current employer’s group plan pays first. That’s a reasonable choice, but until Part B begins you can’t be sold a Medicare Supplement policy. Medigap is built to pay the gaps in both parts, so a buyer without Part B has nothing for most of the benefits to attach to.

Delaying Part B also moves your one-time Medigap open enrollment period. It starts in the first month you’re both 65 or older and enrolled in Part B, so a 68-year-old retiree who adds Part B next spring gets six protected months starting then. The application paperwork is covered in how to sign up for Medigap, and the timing of each application window is covered in can I sign up for a Medicare Supplement plan anytime.

A Medicare Supplement policy only pays alongside Original Medicare. It won’t pay copays, deductibles or premiums in a Medicare Advantage plan. Medicare.gov lists it as illegal for anyone to sell you a Medigap policy if they know you’re in a Medicare Advantage plan, unless you’re switching back to Original Medicare.

In practice, a Medicare Advantage member can apply for a supplement, as long as the policy’s start date lines up with the day the Advantage plan ends. Whether the insurer must accept you is another matter. People who joined Medicare Advantage when first eligible at 65, or who dropped a Medigap policy to try Advantage for the first time, and who leave within 12 months, generally have a federal right to buy a policy without health questions, explained in the Medigap trial right. KFF counts 19 states that widen who gets that trial period, and Maine stretches it to three years. For the trade-offs between the two paths, see Medigap vs Medicare Advantage.

Searches that pair Medicare with Medicaid, or ask about being dual eligible, regularly land on this site. The short answer is that federal law bars the sale of a Medigap policy to most people with both programs. CMS describes it as longstanding federal law, and KFF’s 2026 review says plainly that Medigap insurers can’t sell policies to people with Medicaid. Full Medicaid already covers most Medicare cost-sharing, so a supplement would pay for little.

CMS names two exceptions: when the state Medicaid program chooses to pay the Medigap premium, and when Medicaid helps only with Medicare premiums, as in the Specified Low-Income Medicare Beneficiary (SLMB) and Qualifying Individual (QI) programs. Other Medicare Savings Program levels may be treated differently by state, so confirm with your state’s insurance department before applying.

People who get Medicare early because of a disability, End-Stage Renal Disease (ESRD) or ALS are only eligible to buy a Medigap policy where state law says so. KFF’s October 13, 2026 review breaks this down further than a simple yes or no: of the 38 states with an under-65 requirement for disabled enrollees, 27 require every plan type, 28 states name ESRD explicitly, and 25 name ALS. California, Massachusetts, Vermont and Nebraska carve ESRD out. Twelve states and DC have no requirement.

Under-65 premiums can be much higher than age-65 rates unless the state limits them. Whatever happens before 65, turning 65 starts a fresh 6-month open enrollment period for anyone already on Part B. State-by-state details are in Medicare Supplement guaranteed issue rights by state.

Since January 1, 2020, federal law has kept Plans C and F, the plan letters that pay the Part B deductible, away from people new to Medicare. The test is when you first became eligible for Medicare, not when you enrolled. Medicare.gov says someone eligible before January 1, 2020 who hasn’t yet enrolled may still be able to buy Plan C or F.

That creates an edge case few guides spell out. A worker born in November 1954 turned 65 in November 2019. Even if she delays Part B until 2027, she can still be sold Plan F where an insurer offers it. A coworker born in February 1955 turned 65 in February 2020 and can’t. Someone who got Medicare through disability in 2018 also keeps Plan F eligibility. Everyone else picks from the remaining letters, with Medicare Supplement Plan G the closest match to F. Costs for those who still qualify are in high deductible Plan F.

Medicare.gov is direct on the last point: a Medigap policy only covers one person. Each spouse qualifies on their own Medicare record, so a 66-year-old can buy now while a 62-year-old spouse waits. Household pricing rules are in the Medicare Supplement household discount. Federal rights tied to losing employer or retiree coverage are listed in open enrollment vs guaranteed issue.

Meeting every condition above only gets your application considered. Outside your 6-month window and without a guaranteed issue right, most states let insurers ask health questions and decline you or charge more; the kinds of questions are in Medigap underwriting questions. Even an accepted policy may delay paying for a condition you already have, as explained in Medicare Supplement pre-existing conditions.

The strongest moment to buy is covered in our guide to Medicare Supplement open enrollment. A licensed agent can check which row fits you before you apply.

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