What happens when you lose your Medicare Card? How do you get it replaced? The easiest way to get a new Medicare Card is at http://mymedicare.gov. You can order a replacment card by logging into your account there. If you do not have an account there you can register for one. Or you can go to the Social Security Site at the Card Replacement Section You will need information to prove your identify, such as your social security number, date of birth, and possibly other information that only you would know.