To enroll in Medicare you must be a US citizen or permanent resident alien that has lived in the United States for at least 5 years.

The Centers for Medicare and Medicaid Services have rules on when you become eligible for the Medicare Initial Enrollment Period.

• Three months before you turn 65
• The month you turn 65
• Three months after you turn 65
• If you retire after 65, enrollment depends on when your employer-sponsored health insurance ends.