Medicare is the U.S. government's health insurance program for people age 65 or older. Certain people under age 65 can qualify for Medicare, too, including those with disabilities, permanent kidney failure or amyotrophic lateral sclerosis. Medicare helps with the cost of health care, but it does not cover all medical expenses or the cost of most long-term care. The program has four parts: Part A is hospital insurance. Part B helps pay for medical services that Part A doesn't cover. Part C is called Medicare Advantage. If you have Parts A and B, you can choose this option to receive all of your health care through a provider organization, like an HMO. Part D is prescription drug coverage . It helps pay for some medicines.