Short answer
Part D and Medigap are separate, so adding a drug plan does not change your supplement.
Medicare.gov says a Medigap policy supplements Original Medicare and that Medigap sold after 2005 does not include drug coverage, so you join a separate Part D plan for prescriptions. The two are different policies. Medicare.gov lists only nonpayment, application fraud, or the insurer leaving the market as reasons a Medigap policy can end, and enrolling in Part D is not one of them.
Start here
What you actually came to find out
Plain answers first. Sources stay below for checking details.
Will Part D cancel my Medigap?
No. Medicare.gov treats them as separate policies.
Why do I need Part D at all?
Medigap sold after 2005 does not include drug coverage.
Can a company drop my Medigap?
Only for nonpayment, application fraud, or leaving the market.
When should I add it?
Watch the Part D penalty if you go without creditable coverage.
Two policies
Separate
Medicare.gov says Medigap supplements Original Medicare and Part D is its own plan.
Source trail: Medicare.gov
Drug coverage
Not in Medigap
Medicare.gov says Medigap sold after 2005 does not include drug coverage.
Source trail: Medicare.gov
Keeping Medigap
Protected
Medicare.gov lists only nonpayment, fraud, or insurer exit as reasons it ends.
Source trail: Medicare.gov
Late penalty
1% per month
Medicare.gov says the Part D penalty grows without creditable coverage.
Source trail: Medicare.gov
The real planning question is whether a standalone Part D plan plus your current Medigap covers your prescriptions for less than you pay out of pocket now.
Neutral landscape
The shape of the question
Medicare.gov is the main source because it explains that Medigap supplements Original Medicare and that newer Medigap does not include drug coverage.
Source trail: Medicare.gov
The drug-plan question comes next. Medicare.gov says prescriptions come through a separate Part D plan.
Source trail: Medicare.gov
The worry about losing Medigap is answered by the same page, which lists the only reasons a policy can be dropped.
Source trail: Medicare.gov
Timing matters because Medicare.gov ties the Part D late penalty to going without creditable coverage.
Source trail: Medicare.gov
Curator core
What the authorities say
These sources are here for the reader who wants to check the work. The plain-English answer stays above them.
Source 01
Medicare.gov
How Medigap Works
Medicare.gov explains that Medigap supplements Original Medicare, that policies sold after 2005 do not include drug coverage, and how Medigap pays after Medicare.
Source framing
Medicare.gov says a Medigap policy is a supplement to Original Medicare, that Medigap sold after 2005 does not include drug coverage, and that Medigap is different from a Medicare Advantage Plan.
Strongest for: how Medigap supplements Original Medicare and pairs with Part D
Read at Medicare.govSource 02
Medicare.gov
Medicare Part D
Medicare.gov explains Part D drug coverage and the late enrollment penalty for going without creditable drug coverage.
Source framing
Medicare.gov says the Part D late enrollment penalty adds 1 percent for each month you could have had Part D but did not, without creditable drug coverage.
Strongest for: Part D enrollment and the late enrollment penalty
Read at Medicare.govPlain-English forks
The forks people face
Most retirement questions hide a few smaller decisions. These are the practical pieces that change the plan.
Do you already have creditable drug coverage?
Why it matters: Creditable coverage is what protects you from the Part D late penalty.
In real life: This fork decides whether delaying Part D has a cost.
What to look at: What to look at: your plan’s creditable-coverage notice.
Is your Medigap a newer policy?
Why it matters: Medigap sold after 2005 does not include drugs, so Part D is the path.
In real life: This fork tells you whether you need a separate drug plan at all.
What to look at: What to look at: your Medigap policy documents.
How much do your prescriptions cost now?
Why it matters: A Part D plan is worth comparing against your current out-of-pocket spend.
In real life: This fork is the dollars-and-cents decision.
What to look at: What to look at: the Medicare Plan Finder drug-cost estimate.
Common questions
Quick answers
Short, plain answers for the questions people usually have next. The source trail stays available below.
Will enrolling in Part D cancel my Medigap policy?+
No. Medicare.gov treats Medigap and Part D as separate policies, and enrolling in Part D is not a reason a Medigap policy can be dropped.
Why does my Medigap not cover drugs?+
Medicare.gov says Medigap policies sold after 2005 do not include prescription drug coverage.
What are the only reasons my Medigap can be dropped?+
Medicare.gov says nonpayment of premiums, fraud on the application, or the insurance company becoming insolvent or leaving the market.
What happens if I skip Part D?+
Medicare.gov says the Part D late enrollment penalty adds 1 percent for each month you could have had Part D but did not, without creditable coverage.
Can I have both Medigap and Part D?+
Yes. Medicare.gov describes them as separate policies that work alongside Original Medicare.
How this page is curated
This page uses Medicare.gov how-Medigap-works and the Medicare Part D page. It keeps the supplement and the drug plan separate because Medicare.gov treats them as two policies.
Read the planner methodologyTrust anchor
Sources used on this page
Every source named above is listed here in one place.
Medicare.gov. How Medigap Works
https://www.medicare.gov/health-drug-plans/medigap/basics/how-medigap-worksMedicare.gov. Medicare Part D
https://www.medicare.gov/health-drug-plans/part-d
Before you act on this
This plan is educational. It is not personalized financial, tax, or insurance advice. Projections illustrate the math, they do not predict the future. Talk to your own licensed financial professional before acting on any of it.