Can Medicare deny you for pre-existing conditions?

No. Original Medicare (Parts A and B) and Medicare Advantage plans cannot deny enrollment based on pre-existing conditions. This is a federal protection. The only exception is Medigap: outside your 6-month Open Enrollment Period, Medigap insurers can use medical underwriting and may deny your application based on health history.

Is there a waiting period for pre-existing conditions with Medicare?

No. Original Medicare and Medicare Advantage have no waiting periods for pre-existing conditions. Coverage begins on your effective date for all conditions. Medigap plans enrolled during your OEP also have no waiting period. However, if you enroll in Medigap outside your OEP and are accepted with underwriting, the insurer may impose a waiting period of up to 6 months for conditions treated in the 6 months before your policy start date.

What pre-existing conditions does Medicare cover?

Medicare covers all pre-existing conditions including diabetes, heart disease, cancer, COPD, arthritis, kidney disease, Alzheimer's, Parkinson's, multiple sclerosis, and any other chronic or acute condition. There is no list of excluded conditions. If a service is medically necessary and covered by Medicare, it is covered regardless of when the condition was diagnosed.

Does Medicare Advantage cover pre-existing conditions?

Yes. Medicare Advantage plans are required by federal law to accept all Medicare-eligible beneficiaries regardless of health status. They cannot deny enrollment, charge higher premiums, or exclude coverage for any pre-existing condition. However, out-of-pocket costs (copays, coinsurance) for managing chronic conditions vary by plan.

Can I get a Medigap plan with a pre-existing condition?

Yes, if you apply during your 6-month Medigap Open Enrollment Period (starts the month your Part B begins). During this window, insurers must accept you at standard rates regardless of health. Outside this window, you may be denied or charged more. Some states (New York, Connecticut, Massachusetts, Maine, Vermont) offer year-round guaranteed issue protections.

What happens if I miss my Medigap Open Enrollment Period?

If you miss your OEP, Medigap insurers can use medical underwriting to evaluate your application. They may deny coverage, charge higher premiums, or impose a pre-existing condition waiting period. Your alternatives include staying on Original Medicare and paying the 20% coinsurance out of pocket, enrolling in a Medicare Advantage plan (which must accept you), or waiting for a Guaranteed Issue event.

Does Medicare cover pre-existing conditions for people under 65?

Yes. People under 65 who qualify for Medicare through disability (after 24 months of SSDI) or specific conditions (ALS, ESRD) receive the same pre-existing condition protections. Original Medicare and Medicare Advantage cannot deny coverage based on health status. However, Medigap protections for those under 65 vary by state, as not all states require insurers to offer Medigap to beneficiaries under 65.

How is Medicare different from private insurance for pre-existing conditions?

Before the ACA (2014), private insurers could deny coverage for pre-existing conditions. Medicare has never had this restriction. Since its creation in 1965, Medicare has accepted all eligible beneficiaries regardless of health. Today, both Medicare and ACA-compliant private plans cover pre-existing conditions, but Medicare's Medigap market still allows underwriting outside the OEP, which is a key difference from ACA marketplace plans.

Can Medicare deny you for pre-existing conditions?

No. Original Medicare (Parts A and B) and Medicare Advantage plans cannot deny enrollment based on pre-existing conditions. This is a federal protection. The only exception is Medigap: outside your 6-month Open Enrollment Period, Medigap insurers can use medical underwriting and may deny your application based on health history.

Is there a waiting period for pre-existing conditions with Medicare?

No. Original Medicare and Medicare Advantage have no waiting periods for pre-existing conditions. Coverage begins on your effective date for all conditions. Medigap plans enrolled during your OEP also have no waiting period. However, if you enroll in Medigap outside your OEP and are accepted with underwriting, the insurer may impose a waiting period of up to 6 months for conditions treated in the 6 months before your policy start date.

What pre-existing conditions does Medicare cover?

Medicare covers all pre-existing conditions including diabetes, heart disease, cancer, COPD, arthritis, kidney disease, Alzheimer's, Parkinson's, multiple sclerosis, and any other chronic or acute condition. There is no list of excluded conditions. If a service is medically necessary and covered by Medicare, it is covered regardless of when the condition was diagnosed.

Does Medicare Advantage cover pre-existing conditions?

Yes. Medicare Advantage plans are required by federal law to accept all Medicare-eligible beneficiaries regardless of health status. They cannot deny enrollment, charge higher premiums, or exclude coverage for any pre-existing condition. However, out-of-pocket costs (copays, coinsurance) for managing chronic conditions vary by plan.

Can I get a Medigap plan with a pre-existing condition?

Yes, if you apply during your 6-month Medigap Open Enrollment Period (starts the month your Part B begins). During this window, insurers must accept you at standard rates regardless of health. Outside this window, you may be denied or charged more. Some states (New York, Connecticut, Massachusetts, Maine, Vermont) offer year-round guaranteed issue protections.

What happens if I miss my Medigap Open Enrollment Period?

If you miss your OEP, Medigap insurers can use medical underwriting to evaluate your application. They may deny coverage, charge higher premiums, or impose a pre-existing condition waiting period. Your alternatives include staying on Original Medicare and paying the 20% coinsurance out of pocket, enrolling in a Medicare Advantage plan (which must accept you), or waiting for a Guaranteed Issue event.

Does Medicare cover pre-existing conditions for people under 65?

Yes. People under 65 who qualify for Medicare through disability (after 24 months of SSDI) or specific conditions (ALS, ESRD) receive the same pre-existing condition protections. Original Medicare and Medicare Advantage cannot deny coverage based on health status. However, Medigap protections for those under 65 vary by state, as not all states require insurers to offer Medigap to beneficiaries under 65.

How is Medicare different from private insurance for pre-existing conditions?

Before the ACA (2014), private insurers could deny coverage for pre-existing conditions. Medicare has never had this restriction. Since its creation in 1965, Medicare has accepted all eligible beneficiaries regardless of health. Today, both Medicare and ACA-compliant private plans cover pre-existing conditions, but Medicare's Medigap market still allows underwriting outside the OEP, which is a key difference from ACA marketplace plans.

Does Medicare Cover Pre-Existing Conditions? (2026 Guide)

Quick Answer

Original Medicare: CoveredMedicare Advantage: CoveredMedigap (during OEP): Covered

Yes. Medicare covers pre-existing conditions without waiting periods, exclusions, or higher premiums. Original Medicare (Parts A and B) accepts all eligible beneficiaries regardless of health status. Medicare Advantage plans cannot deny enrollment based on pre-existing conditions. Medigap plans cover pre-existing conditions when you enroll during your 6-month Open Enrollment Period, which starts the month your Part B begins. Outside that window, insurers can use medical underwriting and may deny coverage or impose a waiting period of up to 6 months.

Coverage Comparison by Plan Type

Plan Type	Coverage	Notes
Original Medicare (Parts A & B)	Fully Covered	No health questions, no waiting periods, no denials based on health status
Medicare Advantage (Part C)	Fully Covered	Cannot deny enrollment or charge more for pre-existing conditions
Medigap (Medicare Supplement)	Covered During OEP	Guaranteed issue during 6-month OEP; underwriting applies outside OEP
Medicare Part D	Fully Covered	Cannot deny enrollment; formulary determines which drugs are covered

Understanding Your Coverage Options

Original Medicare (Part a & B)

Covered

Every beneficiary gets an enrollment window called your Initial Enrollment Period. At this time, you can enroll in Medicare without any health questions. Once you enroll in Part B, you’ll have another enrollment window that allows you to enroll in a supplemental plan without pre-existing conditions impacting your chances of being accepted into the plan.

Medicare Advantage (Part C)

Covered

Yes, Medicare Advantage plans will cover pre-existing conditions. This is one of the features that attract beneficiaries to Advantage plans. However, they don’t consider all the out-of-pocket costs you have to pay when you go to the doctor. Those with a chronic condition will get better long-term benefits with a Medicare Supplement (Medigap) Plan.

Medicare Supplement (Medigap)

Varies

Yes, Medicare Supplements cover pre-existing conditions as long as you enroll at the right time. When purchasing a Medicare Supplement plan during your Medigap Open Enrollment Period, you’re automatically eligible for coverage.

During this period, you’re granted Guaranteed Issue Rights. Private insurance companies offering Medigap plans cannot deny you coverage or increase your rates due to any pre-existing health conditions.

If you don’t enroll during your Open Enrollment Period, you can be denied coverage or charges a higher premium due to pre-existing health conditions.

✦ Frequently Asked Questions

David Haass

Author

David Haass is a licensed Medicare expert who has been helping beneficiaries navigate their Medicare options for over a decade.

Ashlee Zareczny

Reviewer

Ashlee Zareczny is a licensed Medicare agent dedicated to helping those eligible for Medicare find the best coverage options.

Does Medicare Cover Pre-Existing Conditions?

Quick Answer

Coverage Comparison by Plan Type

Understanding Your Coverage Options

Original Medicare (Part a & B)

Medicare Advantage (Part C)

Medicare Supplement (Medigap)

✦ Frequently Asked Questions

Related Coverage Topics

Can You Be Denied a Medicare Supplement Plan?

Medicare Supplement Open Enrollment Period

Does Medicare Cover Dental Implants?

Does Medicare Cover Hearing Aids?

Medicare Coverage for Disabled Individuals under 65

Your Medicare Rights and Protections

Need Help Understanding Your Coverage?