 You're first eligible to sign up for Medicare three months before you turn 65, and you have a total of seven months to get your enrollment done. So that means in addition to the three months before your birth month, your birth month, and then you have the three months after as well. You may be eligible to get Medicare earlier if you have a disability, end-stage renal disease, or ALS, which is also Lou Gehrig's disease, and there are certain circumstances where you can delay your Medicare without fear of penalties, which are called special enrollment periods.