How Old Do You Have To Be To Sign Up For Medicare? 
You have to be age 65 to sign up for Medicare , unless you have end stage renal disease or Lou Gherig 's disease -LRB- within parameters set forth by Medicare -RRB- . You will receive Medicare at an age younger than 65 if you have been on Social Security Disability for 24 months and are under age 65 . If you are receiving Social Security benefits at age 65 , you will be automatically enrolled in Medicare at age 65 . 