Medigap is Medicare Supplement Insurance that helps fill "gaps" in Original Medicare and is sold by private companies. Original Medicare pays for much, but not all, of the cost for covered health care services and supplies. A Medicare Supplement Insurance (Medigap) policy can help pay some of the remaining health care costs, like:

Some Medigap policies also cover services that Original Medicare doesn't cover, like medical care when you travel outside the U.S. If you have Original Medicare and you buy a Medigap policy, here's what happens: