Individuals are eligible to enroll once they reach age 65. Persons under the age of 65 who have received Social Security Disability Insurance (SSDI) benefits for at least 24 months are automatically enrolled in Medicare and are entitled to premium-free Part A benefits. Individuals receiving Social Security retirement benefits are automatically enrolled in traditional Medicare (Part A and Part B) once they turn 65. Enrollment in Medicare is also automatic after the 24-month waiting period for people who receive SSDI benefits.
The waiting period is waived for individuals who have qualified for SSDI due to amyotrophic lateral sclerosis. Individuals diagnosed with end-stage renal disease (ESRD) are eligible for Medicare without first having to receive SSDI benefits. In addition, individuals who were diagnosed with a specific lung disease or type of cancer and lived in an area subject to a public health emergency declaration by the Environmental Protection Agency for a specified period before diagnosis are entitled to Part A benefits and eligible to enroll in Part B.