What is Medicare and Who is Eligible?

At its core, Medicare is a federal health insurance program primarily for people aged 65 or older. It was signed into law in 1965 to provide a safety net for retirees, ensuring access to medical care without the full burden of private insurance costs. It is not just for seniors, though. Younger people with certain disabilities or individuals with End-Stage Renal Disease (ESRD) or Amyotrophic Lateral Sclerosis (ALS, also known as Lou Gehrig’s disease) can also qualify.

For most people, eligibility begins when you turn 65. If you are already receiving Social Security or Railroad Retirement Board benefits for at least four months before you turn 65, you will likely be enrolled in Medicare Parts A and B automatically. Your Medicare card will be mailed to you about three months before your 65th birthday, with coverage starting on the first day of your birthday month.

If you are not yet receiving Social Security benefits, you will need to sign up for Medicare yourself. This is a crucial step. The main time to do this is during your Initial Enrollment Period (IEP). This is a seven-month window that starts three months before the month you turn 65, includes your birthday month, and ends three months after your birthday month. Signing up during this period helps you avoid potential late enrollment penalties, which can be added to your monthly premiums for as long as you have coverage.

Think of eligibility as the key that unlocks the door to Medicare. Once you have that key, the next step is to understand what is behind the door—the different parts of the program that will make up your health coverage.