Who Is Medicare Administered By? 
Medicare is administered by the Center for Medicare and Medicaid Services -LRB- CMMS -RRB- . This is a division of Social Security charged with setting the rules and guidelines of Medicare and Medicare related matters . Original Medicare , Medicare Advantage Plans , and Medicare Prescription Drug Plans fall under this umbrella . If you are in original Medicare then Medicare will pay any claims . If you select a Medicare Advantage Plan , then Medicare pays the insurance company to administer the claims . 