Original Medicare and Part C plans can’t deny you insurance coverage based on preexisting conditions. A waiting period to enroll in Medicare due to preexisting conditions only applies to enrolling in a Medigap plan.

Original Medicare (parts A and B), Medicare Advantage (Part C), or Part D drug plans don’t have a waiting period associated with preexisting conditions.

Some enrollment and waiting periods related to preexisting conditions may apply if you want to enroll in a Medicare supplement (Medigap) plan.

Medicare supplement plans, or Medigap plans, are available through private companies approved by Medicare. These plans help cover expenses that Original Medicare doesn’t cover, such as deductibles, coinsurance, and copayments.

Because these plans don’t directly provide medical coverage and don’t meet the minimum essential coverage of the Affordable Care Act (ACA), insurers offering these plans can deny coverage based on preexisting conditions. However, other federal laws still impose some limitations. One of these limitations happens during the initial enrollment period.

When you turn 65 years old and sign up for Medicare Part B, you have a 6-month Medigap open enrollment period. During this time, you can enroll in any Medigap policy without needing medical underwriting. This means that insurers can’t refuse you coverage due to preexisting conditions, allowing you to choose the plan that suits you best.

After this enrollment window closes, you might face higher costs or coverage denial. If you’re under 65 years old and qualify for Medicare due to a disability, you may need to wait until you turn 65 years old before Medigap insurers must insure you by law.

At any point outside the 6-month enrollment period, insurers can deny you a Medigap plan based on preexisting conditions.

Additional exceptions exist during which you have protection from coverage denial even outside of this period. These are known as “guaranteed issue rights.” They are:

  • Your Medicare Advantage Plan is changing, no longer available in your region, or you’re relocating beyond its service area.
  • You have Original Medicare and an employer or union plan that provides coverage after Medicare, including the Consolidated Omnibus Budget Reconciliation Act (COBRA), and that coverage is ending.
  • You possess Original Medicare and a Medicare SELECT policy but are moving beyond the policy’s service area.
  • You initially joined a Medicare Advantage plan or Program of All-Inclusive Care for the Elderly (PACE) when you were first eligible for Medicare and wish to switch to Original Medicare within the first year.
  • You changed to a Medicare Advantage plan (or Medicare SELECT) within the last year and now want to switch again.
  • Your Medigap insurance company goes bankrupt or cancels your policy through no fault.
  • You change or cancel your Medicare Advantage plan or Medigap policy due to a violation or misleading information by the provider.

Certain states may impose additional “guaranteed rights” beyond what the federal government requires.

You may have had your current Medigap policy for more than 6 months and want to enroll in a plan with the same benefits. In that case, the new insurance company can’t exclude you based on preexisting conditions or make you wait for coverage.

However, 10 different Medigap plans exist that are generally standard throughout the United States, and their specific benefits differ. You may need to wait 6 months to switch from one type of Medigap policy to another. This is known as the preexisting condition waiting period.

Your new policy should consider the months you’ve already had coverage from your current Medigap policy. For instance, if you’ve had coverage for 2 months before switching, your new policy should only require you to wait another 4 months.

Medicare Advantage (Part C) plans must offer the same coverage as Original Medicare (parts A and B). Under the ACA, insurers offering Part C plans can’t deny you coverage based on preexisting conditions.

Since you can only use Medigap to cover Original Medicare costs, you need to drop your Medigap plan if you switch to a Part C plan.

To give you the chance to try out a Part C plan without losing your Medigap coverage, Medicare allows you a 12-month trial period. You might decide to unenroll from this Part C plan and reenroll in Original Medicare within this year. In that case, you can reenroll in your previous Medigap plan or enroll in a new plan without medical underwriting.

Original Medicare (parts A and B), Medicare Advantage (Part C), and Part D prescription plans don’t impose any waiting period for preexisting conditions. Following the implementation of the ACA, these plans can’t refuse coverage due to preexisting conditions.

However, if you’re considering a Medicare supplement (Medigap) plan, specific enrollment and waiting periods for preexisting conditions might still be applicable. These include the initial 6-month enrollment period, guaranteed issue rights, and a 12-month trial period to try out a Part C plan.