All US citizens can enroll in Medicare when they reach 65 years old. Permanent residents who are not citizens can also qualify at 65, as long as they have lived in the US for at least five years.

If you’re under 65, you may be eligible for Medicare if:

• You are permanently disabled and have received Social Security Disability benefits for at least 24 months.
• You have been diagnosed with end-stage renal disease (kidney failure).
• You have been diagnosed with Amyotrophic Lateral Sclerosis (Lou Gehrig’s disease) and are receiving Social Security Disability benefits.