Medicare Supplement Insurance (Medigap) is extra insurance you can buy from a private insurance company to help pay your share of out-of-pocket costs in Original Medicare. 

You can only buy Medigap if you have Original Medicare. Generally, that means you have to sign up for 

Medicare Part A (Hospital Insurance) and Part B (Medical Insurance) before you can buy a Medigap policy. 

You get a 6 month “Medigap Open Enrollment” period, which starts the first month you have Medicare Part B and you’re 65 or older. During this time, you can enroll in any Medigap policy and the insurance company can’t deny you coverage due to pre-existing health problems. After this period, you may not be able to buy a Medigap policy, or it may cost more. Your Medigap Open Enrollment Period is a one-time enrollment.  It doesn’t repeat every year, like the Medicare Open Enrollment Period. 

All Medigap policies are standardized. This means, policies with the same letter offer the same basic benefits no matter where you live or which insurance company you buy the policy from. There are 10 different types of Medigap plans offered in most states, which are named by letters: A-D, F, G, and K-N. Price is the only difference between plans with the same letter that are sold by different insurance companies. 

In some states, you may be able to buy another type of Medigap policy called 

Medicare SELECT. If you buy a Medicare SELECT policy, you have the right to change your mind within 12 months and switch to a standard Medigap policy.    

Every Medigap policy must follow federal and state laws designed to protect you. It’s important to watch out for illegal practices by insurance companies, and protect yourself when you’re shopping for a Medigap policy.  

Medigap plans generally help cover your share of costs for services that are covered by Original Medicare (Part A and Part B). The benefits are different in each plan – you can buy the one that meets your needs. Not all plans are offered in every state.

Medigap policies help cover out-of-pocket costs associated in Original Medicare, like:

• Copayments
• Coinsurance
• Deductibles

Some Medigap policies cover services that Original Medicare doesn't cover, like emergency medical care when you travel outside the U.S. (foreign travel emergency care).

Medigap doesn’t cover everything. Medigap plans generally don’t cover:

• Long-term care (like care in a nursing home)
• Vision or dental care
• Hearing aids
• Eyeglasses
• Private-duty nursing

Note: You can enroll in a separate Medicare drug plan (Part D) if you want prescription drug coverage. Medigap plans sold after 2005 don’t include prescription drug coverage.