Can You Change Medicare Supplement Plans With Pre-Existing Conditions?

Changing Medicare Supplement plans with pre-existing conditions is possible, but only during a 6-month open enrollment or 63-day guaranteed issue window.

Find the right Medicare Supplement Plans below.

Written by Mark Fitzpatrick

Updated: April 1, 2026

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Key Takeaways

You can change Medicare Supplement plans with pre-existing conditions during two federally protected enrollment windows.

Outside protected windows, insurers in most states can deny or surcharge Medigap applications based on pre-existing conditions.

Federal guaranteed issue rights give you a 63-day window to switch plans after a qualifying event, per CMS.

Four states require year-round Medigap acceptance, and 12 additional states plus Indiana in 2026 offer annual birthday rule protections.

Can Insurers Deny You a Medigap Plan Because of a Pre-Existing Condition?

Medigap insurers in most states can deny an application based on pre-existing conditions, but only outside the federally protected enrollment windows.

Outside a protected window, a Medigap insurer may approve the application with no restrictions if the applicant passes medical underwriting, approve it with a premium surcharge based on health rating (where state law permits), approve it with a waiting period of up to six months for coverage of the flagged condition, or deny coverage outright.

No federal cap limits the size of a premium surcharge outside protected windows in states that permit health-based rating.

WHAT IS MEDICAL UNDERWRITING IN MEDIGAP?

Medical underwriting is how an insurer reviews health history, current diagnoses and prescription drug records before approving, denying or pricing a Medigap application. ACA-compliant health insurance works differently: pre-existing conditions cannot affect enrollment or premiums in individual and small group markets.

When Can You Change Medigap Plans Without Medical Underwriting?

Federal law creates two windows during which Medigap insurers cannot apply medical underwriting, cannot deny an application based on health status and cannot charge a premium surcharge based on pre-existing conditions.

These windows are the Medigap open enrollment period and guaranteed issue rights. The open enrollment period is a one-time window that closes permanently once it expires, while guaranteed issue rights can be triggered multiple times throughout a beneficiary's life by qualifying events.

During Your Medigap Open Enrollment Period

The Medigap open enrollment period is a six-month window that begins on the first day of the month in which a beneficiary is both age 65 or older and enrolled in Medicare Part B. Any Medigap insurer selling plans in the applicant's state must accept the application during this window and cannot deny coverage or charge higher premiums based on health history.

It opens once and doesn't repeat after it closes. The clock starts only when both the age and Part B enrollment conditions are met simultaneously.

When You Have Guaranteed Issue Rights

Guaranteed issue rights are federal protections triggered by qualifying events that give beneficiaries a 63-day window to enroll in a Medigap plan without medical underwriting. Under this window, insurers cannot deny coverage or charge higher premiums based on health status or pre-existing conditions.

The 63-day clock starts on the date prior coverage actually ends, not on the date the beneficiary receives notice that coverage will terminate. This distinction matters because termination notices sometimes arrive weeks before the actual termination date, and beneficiaries who calculate from the notice date may miss the deadline.

What Events Qualify You for Guaranteed Issue Rights?

CMS defines a set of federal triggering events that activate guaranteed issue rights for Medigap enrollment. The 63-day clock begins when coverage under the prior plan ends. Missing that window means losing that protection for the trigger entirely.

Medigap insurers require written proof of the triggering event before processing an application under guaranteed issue. Acceptable documentation includes a plan termination letter, an employer benefit end-date confirmation or other official records.

Medicare Advantage Plan Termination

Your Medicare Advantage plan stops participating in Medicare or ends coverage in your service area. CMS designates this event as a guaranteed issue trigger, giving you 63 days from the plan's termination date to apply for a Medigap plan without health review.

Loss of Employer or Union Group Coverage

You lose employer-sponsored or union-sponsored supplemental health coverage that supplements your Medicare benefits. The 63-day window starts from the date your group coverage ends, not from the date you receive the termination notice from your employer.

Moving Outside Your Plan's Service Area

You move permanently outside the service area of your Medicare Advantage or Medicare SELECT plan. The move must be permanent, and you must disenroll from the existing plan before the guaranteed issue window begins.

Returning to Original Medicare Within Your First Year of Medicare Advantage

You enrolled in a Medicare Advantage plan for the first time at age 65 and decide within the first 12 months to return to Original Medicare. CMS extends a trial right that functions as a guaranteed issue trigger for one Medigap plan.

Leaving Medicare Advantage After Switching From a Medigap Plan

You dropped your Medigap plan to join a Medicare Advantage plan and left within the first 12 months. CMS restores a guaranteed issue right so you can re-enroll in the same Medigap plan you previously held or in a comparable one with equal or lesser benefits.

Your Medigap Insurer Goes Bankrupt or Exits Medicare

Your Medigap insurer is declared insolvent or loses its Medicare certification. CMS treats this event as a guaranteed issue trigger and your 63-day window begins on the date the insurer's coverage ends, not the date bankruptcy proceedings begin.

Which States Allow Medigap Plan Changes With Pre-Existing Conditions?

Some states have enacted protections beyond federal guaranteed issue rules, allowing beneficiaries to switch Medigap plans more freely regardless of health status.

Two protection categories exist: year-round open enrollment, available in four states where insurers must accept all Medicare beneficiaries at any time without medical underwriting, and the birthday rule, active in 12 states plus Indiana as of 2026, where beneficiaries have an annual window around their birthday to switch to an equal or lesser benefits plan without medical underwriting.

These protections apply to beneficiaries who qualify for Medicare and reside in the applicable state at the time of application.

State	Protection Type	Annual Window	Underwriting Waived
California	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Connecticut	Year-round open enrollment	Any time	Yes
Idaho	Birthday rule	63 days after birthday	Yes, for plans with same or fewer benefits
Illinois	Birthday rule	45 days after birthday	Yes, for plans with same or fewer benefits
Indiana	Birthday rule (effective 2026)	30 days after birthday	Yes, for plans with same or fewer benefits
Kentucky	Birthday rule	60 days after birthday	Yes, for plans with same or fewer benefits
Louisiana	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Maine	Year-round open enrollment	Any time	Yes
Maryland	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Massachusetts	Year-round open enrollment (state-standardized plans)	Annual open enrollment period	Yes
Nevada	Birthday rule	60 days after birthday	Yes, for plans with same or fewer benefits
New York	Year-round open enrollment	Any time	Yes
Oklahoma	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Oregon	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Utah	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Virginia	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits
Wyoming	Birthday rule	30 days after birthday	Yes, for plans with same or fewer benefits

The birthday rule doesn't give beneficiaries the right to upgrade to a plan with more benefits. In most birthday rule states, the new Medigap plan must have equal or fewer benefits than the plan the beneficiary currently holds. A beneficiary who wants to move to a plan with greater benefits outside these windows is subject to full medical underwriting.

Knowing how Medicare Supplement plan costs vary by letter clarifies the trade-offs between plan letters when upgrading isn't possible under state protections.

How Do You Change Medigap Plans With a Pre-Existing Condition?

Beneficiaries with a confirmed federal guaranteed issue right, or those in a state with birthday rule or year-round open enrollment protections, can use this process. Before starting, confirm the qualifying triggering event and check that the enrollment window is still open.

1
Confirm Your Guaranteed Issue Right or State Eligibility
Identify whether a federal triggering event applies to your situation, such as losing employer coverage, your Medicare Advantage plan terminating or permanently moving outside your plan's service area, or whether you live in a state with a birthday rule or year-round open enrollment.

Keep written documentation of the triggering event, such as a plan termination letter, an employer benefit end-date notice or your birth certificate, because the new Medigap insurer will request proof before processing your application under guaranteed issue.

Applying without a confirmed triggering event or state protection means the insurer can apply full medical underwriting, which may result in a denial or a premium surcharge based on your health history.
2
Compare Plan Letters Available in Your State
Review the Medicare Supplement plan letters available in your state, focusing on Plan G and Plan N, which are the two most enrolled plans since Plan F closed to applicants new to Medicare in 2020, per CMS.

Benefits for the same plan letter are standardized by CMS regardless of insurer, so the only variables across companies for the same letter are the monthly premium and the pricing structure (attained-age, issue-age or community-rated).
3
Apply Directly With the New Insurer During Your Window
Contact the insurer of the plan you want and complete the application, stating clearly that you are applying under guaranteed issue rights and identifying the specific triggering event by name. Submit your application as early in the 63-day window as possible to allow processing time and reduce the risk of a coverage gap between your old plan ending and your new plan starting.
4
Confirm the Effective Date Before Canceling Your Old Plan
Once the new insurer confirms your coverage effective date in writing, notify your current Medigap insurer in writing that you are canceling your policy, using the cancellation procedure required in your state. Canceling your existing plan before receiving written confirmation of the new plan's start date creates a coverage gap, which could leave you responsible for Medicare's 20% coinsurance on Part B services with no annual cap.

Set the cancellation date for your old plan to match the new plan's effective date exactly so there's no gap and no period where you're paying premiums on two Medigap plans simultaneously.
5
Notify Your Health Care Providers of the Coverage Change
Before your first medical appointment under the new Medigap plan, inform your primary care physician and any active specialists of the insurer change so their billing staff can route secondary claims to the correct Medigap company.

Your providers bill Original Medicare first for covered services and Medicare pays its portion directly; the Medigap insurer then receives the secondary claim for its share, meaning a billing address error at this step can delay reimbursement by weeks.

What Are Your Options if You're Denied a Medigap Plan?

A Medigap denial under medical underwriting doesn't eliminate all coverage options. Three primary paths are available after a denial: applying to a different Medigap insurer, switching to Medicare Advantage and contacting a State Health Insurance Assistance Program (SHIP) counselor to identify state-specific options.

Apply to Additional Medigap Insurers

Each Medigap insurer maintains its own underwriting criteria. A denial from one company is not binding on others. Applying to multiple insurers in sequence increases the likelihood of finding coverage, though premiums and underwriting decisions will vary by company.

Enroll in Medicare Advantage During Annual or Special Enrollment

Medicare Advantage plans cannot deny enrollment based on pre-existing conditions during the annual enrollment period (October 15 to December 7) or during applicable special enrollment periods, per CMS.

Contact Your State SHIP Office for Free Guidance

State Health Insurance Assistance Program (SHIP) counselors provide free, unbiased guidance on Medigap eligibility, state-specific protections and coverage options for beneficiaries with pre-existing conditions. SHIP offices are federally funded and available in all 50 states.

Check for State High-Risk Pool or Additional State Protections

A small number of states maintain high-risk pools or extended guaranteed issue protections for Medigap applicants who have been denied under medical underwriting. Contact your state insurance commissioner's office to confirm which protections, if any, apply in your state.

Bottom Line

In most states, insurers can deny a Medigap application based on pre-existing conditions once a guaranteed issue period or state birthday window has passed. Apply as soon as possible if you're within 63 days of losing prior coverage or your state's annual birthday window is approaching.

A missed deadline removes that protection entirely, and full medical underwriting kicks in, opening the door to denial or premium surcharges.

Medicare Supplement Plan Changes With Pre-Existing Conditions: FAQ

We've answered the most frequently asked questions about changing Medicare Supplement plans with pre-existing conditions. These cover guaranteed issue rights, state birthday rules and how medical underwriting applies:

Does Medicare cover pre-existing conditions even if Medigap won't?

Original Medicare Parts A and B cover medically necessary services regardless of pre-existing conditions. Medigap's pre-existing condition rules affect only the secondary payment, not Original Medicare's coverage of the underlying service.

Can a Medigap insurer charge you more because of a pre-existing condition?

Outside the open enrollment period and guaranteed issue windows, Medigap insurers in most states may charge a higher premium based on medical underwriting results. In the four year-round open enrollment states (Connecticut, Maine, Massachusetts and New York) and during active birthday rule windows, premium surcharges based on health status are not permitted under state law.

What is the Medigap open enrollment period and when does it start?

The Medigap open enrollment period is a six-month window starting on the first day of the month the beneficiary is both age 65 or older and enrolled in Medicare Part B. During this window, insurers selling plans in that state must accept the application and cannot use health status to deny coverage or add a surcharge.

Can you switch from Medicare Advantage to a Medigap plan with a pre-existing condition?

Switching from Medicare Advantage to a Medigap plan without medical underwriting is possible during specific guaranteed issue windows only: the 12-month trial period when first joining Medicare Advantage at age 65, or when a Medicare Advantage plan terminates. Outside those windows, the Medigap insurer can apply full underwriting.

Do all Medicare Supplement plan letters carry the same pre-existing condition rules?

Federal pre-existing condition and medical underwriting rules apply equally to all standardized Medigap plan letters (A through N). The distinction is timing, not plan letter: the same underwriting-free protections during open enrollment or guaranteed issue windows apply to Plan G, Plan N and every other letter. No plan letter receives different treatment under federal underwriting rules.

About Mark Fitzpatrick

Mark Fitzpatrick, a Licensed Property and Casualty Insurance Producer, is MoneyGeek's resident Personal Finance Expert. He has analyzed the insurance market for over five years, conducting original research for insurance shoppers. His insights have been featured in CNBC, NBC News and Mashable.

Fitzpatrick holds a master’s degree in economics and international relations from Johns Hopkins University and a bachelor’s degree from Boston College. He's also a five-time Jeopardy champion!

He writes about economics and insurance, breaking down complex topics so people know what they're buying.

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