Four categories of immigration status now determine who can get a Medicare card: U.S. citizen or national, lawful permanent resident, Cuban-Haitian entrant, or Compact of Free Association migrant. The Centers for Medicare & Medicaid Services’ 2027 Medicare & You handbook flags the requirement as new, stating a person must fall into one of those four groups to get Part A and Part B benefits or join a Medicare health or drug plan. Separate CMS enrollment guidance ties the same rule to federal regulation, instructing plans to deny any enrollment request once the agency’s own records fail to confirm a person’s citizenship or lawful presence.
The Citizenship and Lawful-Presence Test in CMS Regulation
Federal Medicare Advantage and Part D regulation sets the legal floor for this requirement. Under 42 CFR Sections 422.50 and 423.30, an individual is eligible to enroll in a plan only if they are a United States citizen or lawfully present in the country, as determined under 8 CFR Section 1.3. If the Centers for Medicare & Medicaid Services determines an applicant does not meet that standard at the time of enrollment, it notifies the plan, and the plan is required to deny the enrollment request once that notice arrives.
CMS spells out the same mechanics in its enrollment and disenrollment guidance for plan year 2026, which lists citizenship or lawful presence alongside three other baseline conditions every applicant must clear: having Medicare Part A or Part B, permanently residing within a plan’s service area, and completing an enrollment request. The guidance treats the status check as a gate, not a formality: an application that fails it does not proceed to the plan’s other eligibility questions.
The requirement is not limited to private Medicare Advantage or Part D plans. CMS’s 2027 Medicare & You handbook flags the same four qualifying categories (U.S. citizen or national, lawful permanent resident, Cuban-Haitian entrant, or Compact of Free Association migrant) as a new condition to get Part A and Part B benefits or join any Medicare health or drug plan, extending the same test to original, fee-for-service Medicare.
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How CMS Verifies Status Without Requesting Paperwork
The verification happens on CMS’s side, not the applicant’s. The agency’s enrollment guidance states that CMS uses its own systems of records, including data drawn from Social Security Administration systems, as the primary resource for determining lawful presence status. A plan may not request documentation of citizenship or immigration status directly from the person applying. In practice, an applicant does not hand a passport or green card to a Medicare Advantage or Part D plan; the plan instead waits for CMS’s own systems to confirm, or fail to confirm, that status.
The rule carries one built-in exception. If CMS’s systems show that an applicant will have lawful presence status on or before the enrollment’s effective date, the plan must still accept and process the request rather than deny it outright. That single exception is the clearest sign the test looks forward as well as backward: CMS is not only checking a static record, it is checking whether a pending status change is already documented on the government’s side before the coverage date arrives.
When an applicant’s own evidence of status conflicts with what CMS’s systems show, the guidance does not route the dispute back to the plan for a decision. It directs the individual to a Social Security field office to have the status reviewed and adjusted, and it points applicants toward the Social Security Office Locator to find the nearest one. That keeps the actual determination inside the federal system rather than in the hands of the private insurer selling the plan.
That structure narrows who actually gets blocked in practice. The people denied are not necessarily people without qualifying status; they are people whose status has not yet been confirmed inside CMS’s own data, since a plan is barred from accepting outside paperwork as a substitute for that confirmation. A citizen or lawful permanent resident whose federal record has not caught up to a recent status change, name change, or data-entry correction can be denied by the same system check meant to catch someone with no qualifying status at all.
What Happens When Status Changes After Enrollment
CMS’s enrollment guidance treats status as something that can change in both directions after a person is already on a plan’s rolls, not just at the moment of application. Its disenrollment procedures list unlawful presence status as its own required disenrollment trigger, in the same section as losing Part A or Part B eligibility, rather than as an optional action a plan may or may not take. An enrollee whose status is later found not to meet the citizenship or lawful-presence standard can be removed from the plan after enrollment, not only screened out before it.
The guidance also builds a pathway in the other direction. A dedicated special enrollment period exists specifically for people who were not lawfully present when they first became eligible for Medicare but later become lawfully present, letting them enroll outside the standard windows once their status changes. That provision only makes sense if the citizenship and lawful-presence test is treated as a live, recheckable condition rather than a one-time box checked at initial sign-up. Status can cost a person coverage, and a later change in that same status can restore the chance to enroll.
Two pieces of the record are still unsettled in what CMS has made public. Neither the enrollment guidance nor the 2027 handbook specifies how often CMS rechecks an enrollee’s status once coverage begins, or how many enrollees the unlawful presence disenrollment trigger has actually affected since the rule took hold. What is confirmed is narrower and more mechanical: eligibility now runs through a federal data match, not a document handed to an insurer, and a mismatch in that match, whatever its cause, is enough on its own to keep a Medicare card from arriving.
This article was produced with AI assistance and reviewed by The Money Overview editorial team.
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