Pre-Existing Conditions and Medicare
Medicare itself doesn't use your health history against you. The exception to know about is Medigap (Medicare Supplement) insurance — and specifically, when you apply for it.
The General Rule
Once you're enrolled, Original Medicare and Medicare Advantage plans cannot deny you coverage, refuse to pay for a covered service, or charge you a higher premium because of your health history or pre-existing conditions. Every Medicare Advantage plan available in your area during an enrollment period you qualify for must accept you, regardless of your health.
The Nuance
Medigap Works Differently
Medigap (Medicare Supplement) policies are sold by private insurers and are treated differently from Medicare itself. Whether your health history matters depends heavily on timing.
During Your Window
Medigap Open Enrollment Period
This is a one-time, 6-month period that starts the month you're both age 65 or older and enrolled in Medicare Part B. During this window, insurers in every state must sell you any Medigap policy they offer, at the same price offered to healthy applicants, regardless of your health history — they cannot deny you or use medical underwriting.
Outside That Window
Medical Underwriting May Apply
If you apply for a Medigap policy outside your Open Enrollment window (and don't have a Guaranteed Issue right — see below), insurers in most states are legally allowed to ask health questions, deny your application, charge a higher premium, or impose a waiting period for pre-existing conditions. Rules vary somewhat by state, since a handful of states have adopted additional protections beyond the federal minimum.
An Important Exception
Guaranteed Issue Rights
Even outside your Medigap Open Enrollment Period, certain situations give you a "Guaranteed Issue" right — meaning an insurer must sell you a Medigap policy without medical underwriting. Common situations include:
• You lose employer or union coverage that had been paying secondary to Medicare
• You move outside your current Medicare Advantage plan's service area
• Your Medicare Advantage plan or Medigap insurer leaves the market or stops offering coverage in your area
• You enrolled in Medicare Advantage when you first became eligible and decide to switch to Original Medicare within the first 12 months ("trial right")
Guaranteed Issue rights come with specific deadlines to apply, so it's worth confirming the exact timeline for your situation with Medicare directly rather than assuming you have unlimited time.