Age 65 or Older
General eligibility: You are 65 or older and are a U.S. citizen or legal resident for at least 5 years.
Premium-free Part A: You qualify if you or your spouse has worked for at least 10 years (40 quarters) in a job where Medicare taxes were paid.
Receiving other benefits: You may be automatically enrolled if you are already receiving Social Security or Railroad Retirement benefits.
Under age 65
Disability: You are eligible if you have been on Social Security Disability Insurance (SSDI) benefits for 24 months.
End-Stage Renal Disease (ESRD): You are eligible if you have permanent kidney failure and receive maintenance dialysis or a kidney transplant.
Lou Gehrig's disease (ALS): You are eligible immediately if you have this condition.
How to Enroll
Initial Enrollment Period (IEP): A 7-month period starting 3 months before your 65th birthday and ending 3 months after.
Automatic enrollment: Some people are automatically enrolled if they start receiving Social Security benefits before age 65.
Enroll online: You can apply for Medicare only online, even if you are still working.
General Enrollment Period (GEP): If you miss your IEP, you can sign up between January 1 and March 31 each year.