While Original Medicare covers a variety of health services, it doesn’t cover everything. You’ll still have to pay cost-sharing requirements, like deductibles, copayments, and coinsurance. Medicare Supplement (also called Medigap) plans help fill the “gaps” in coverage by paying for some of the costs that Original Medicare doesn’t cover.

How Medicare Supplement Plans Work

To enroll in a Medigap plan, you must be enrolled in Original Medicare, Part A and Part B, and live in the service area of the Medigap plan you want to join. If you and your spouse both want Medigap coverage, you must each purchase separate policies. Medicare Supplement plans only cover one person per policy. Keep in mind that not every state offers Medicare Supplement insurance to individuals under 65 (for example, those who qualify for Medicare because of disability). If you’re under 65 and have Medicare, check with your state insurance department to learn if you’re eligible for Medigap coverage in your state.

Medicare Supplement plans only work with Original Medicare. If you are enrolled in a Medicare Advantage plan, a Medigap plan can’t be used to pay for Medicare Advantage costs.