Medigap open enrollment and guaranteed issue rights

Your one-time Medigap window

Federal law gives you a 6-month Medigap Open Enrollment Period. It starts the first month you have Medicare Part B and you're 65 or older. This window happens once: it doesn't repeat every year, the way the fall Medicare Open Enrollment Period does. It starts when you sign up for Part B, even if you sign up for Part B while you still have employer coverage, so the timing of Part B matters.

During those 6 months, an insurance company can't use medical underwriting to turn you down, and insurance companies can't charge you more because of pre-existing health problems. A company can make you wait for coverage related to a pre-existing condition, but it can't make you wait for anything else.

What can happen if you apply later

Once the window closes, the rules change. A company is allowed to deny you a policy if you don't meet its medical underwriting requirements, and a policy you can get may cost more. In other words, if you don't buy within your 6-month open enrollment, any company you apply to can deny coverage based on your health conditions.

Some states give people extra chances to buy, so check with your State Insurance Department if you're past your window.

Guaranteed issue rights

Outside open enrollment, there are certain situations where an insurance company can't deny you a Medigap policy. These are called guaranteed issue rights, or Medigap protections. Common examples include:

Your Medicare Advantage Plan is leaving Medicare, or it didn't follow the rules or misled you.

You dropped a Medigap policy to join a Medicare Advantage Plan for the first time. You get a single 12-month period (your trial right period) to get your Medigap policy back if the same company still sells it.

Your Medigap company went bankrupt, didn't follow the rules or misled you.

Employer or union coverage that worked with your Medicare is ending.

A guaranteed issue right doesn't let you buy any plan you want. Which plans you can buy depends on your situation. In one common case, for example, you have the right to buy Medigap Plan A, B, C, D, F, G, K, or L that's sold by an insurance company in your state. Plans C and F are only for people who were eligible for Medicare before 2020, because new enrollees cannot buy Plans C, F or F High Deductible after January 1, 2020.

Timing and proof

These windows are short. In most cases you can apply as early as 60 days before the date your coverage ends, and no later than 63 days after your coverage ends. Keep any letters, notices, emails or claim denials that show your coverage ended, because you may need to include them with your Medigap application to prove you qualify.

If you have Medicare before 65

Federal law generally doesn't require insurance companies to sell Medigap policies to people under 65, though some states do. If you have Medicare because of a disability or ESRD, you might not be able to buy a Medigap policy until you turn 65, when your own open enrollment window begins.

Once you have a standardized Medigap policy, it is renewed every year, even if you have health problems. To compare the plans themselves, see our guides to what Medigap covers and Medigap Plan G vs Plan N.

Common questions

Last reviewed October 2026. Medicare rules, dates and dollar amounts can change each year; Medicare.gov has the official details.