The Basic Rule: Age 65 or Citizenship and Disability

You can enroll in Medicare if you are 65 or older, or if you are under 65 and have been receiving Social Security Disability Insurance (SSDI) for at least 24 months. You must also be a U.S. citizen or a permanent resident who has lived in the country for at least five consecutive years.

There is one exception: if you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or transplant — you may be covered regardless of age or disability status, though you will need to meet other requirements with your doctor and dialysis center.

Most people become may be able to access the month they turn 65. If you were born on the first of the month, your coverage starts the month before. If you were born on any other day, coverage starts the month you turn 65.

Key Takeaways

  • You are may be able to access for Medicare at 65 if you are a U.S. citizen or permanent resident who has lived here for five consecutive years.
  • You can enroll before 65 if you have been on SSDI for 24 months, or if you have end-stage renal disease.
  • Your enrollment window opens three months before the month you turn 65 and closes three months after — missing it can mean paying higher premiums for life.
  • If you are still working at 65 and have health insurance through your job, you may be able to delay enrollment without penalty if your employer has 20 or more employees.
  • You do not have to do anything if you are already receiving Social Security — Medicare enrollment happens automatically three months before you turn 65.

When You Turn 65: The Enrollment Window

Your Initial Enrollment Period (IEP) lasts seven months: three months before the month you turn 65, the month you turn 65, and three months after. You can enroll during any of these seven months, but the month you turn 65 is the safest choice because coverage starts the first of that month.

If you enroll before the month you turn 65, your coverage will not start until the first of the month you turn 65. If you enroll after that month, your coverage starts the first of the month after you enroll. This matters because any gap means you are uninsured, and you may owe higher premiums later.

If you miss your Initial Enrollment Period, you can still enroll during the General Enrollment Period from January 1 to March 31 each year. However, your coverage will not start until July 1, and you will pay a late enrollment penalty — a permanent increase to your Part B and Part D premiums — for as long as you have Medicare.

If You Are Under 65 and Receiving Disability

If you receive SSDI, Medicare becomes available after you have been on disability for 24 months. You do not have to wait until 65. Your enrollment window works the same way: it opens three months before your 24-month mark and closes three months after.

If you are receiving Railroad Retirement Board (RRB) benefits instead of SSDI, the same 24-month rule applies. You will receive a notice from Social Security or the RRB telling you when you become may be able to access, usually about three months before your coverage can start.

Once you turn 65, you stay on Medicare even if you return to work and your disability benefits stop. You cannot lose Medicare coverage because your circumstances change.

If You Are Still Working at 65

You can delay enrolling in Medicare Part B (doctor and outpatient care) without penalty if you have group health insurance through your current job or your spouse's current job, and your employer has 20 or more employees. This is called the Special Enrollment Period.

You must still enroll in Part A (hospital insurance) at 65 unless you are still working and have group coverage. Part A has no monthly premium for most people, so there is no penalty for enrolling early.

When you leave your job or lose your group coverage, you have eight months to enroll in Part B without paying a late penalty. You must tell Medicare about the change; the coverage does not happen automatically. Contact Social Security or Medicare directly to report the change and enroll.

If You Have End-Stage Renal Disease

If you have permanent kidney failure and need dialysis or a transplant, you may be covered by Medicare regardless of age or disability status. You become may be able to access the month your dialysis treatments begin, or the month of your transplant, whichever comes first.

Your dialysis center or transplant team will help you understand the enrollment process and timeline. Medicare coverage for ESRD works differently from age-based coverage, and your medical team can explain what documents you will need and when to enroll.

Documents You May Need to Verify Your Status

When you enroll, have these documents ready. You do not need all of them, but having them speeds up the process:

  • Your birth certificate or passport (to prove citizenship or permanent residency)
  • Your Social Security card
  • Proof of residency — a recent utility bill, lease, or mortgage statement
  • If you are a permanent resident, your green card or immigration documents
  • If you are on SSDI or RRB, your award letter or benefit statement

If you are already receiving Social Security retirement or disability benefits, Medicare will have most of this information already. You will not need to submit documents again unless Medicare asks.

What Happens If You Do Not Enroll on Time

If you miss your Initial Enrollment Period and do not have a reason that qualifies for a Special Enrollment Period, you will pay a late enrollment penalty for the rest of your life. The penalty is 10 percent of the Part B premium for each full 12 months you were may be able to access but not enrolled. For Part D (prescription drug coverage), the penalty is 1 percent of the national average premium for each month you were without coverage.

These penalties are permanent. Even if you enroll years later, you will keep paying them. The only way to avoid them is to enroll during your Initial Enrollment Period or to have a may have access to reason for a Special Enrollment Period.

Frequently Asked Questions

What if I am a permanent resident but not yet a citizen?

You must have been a permanent resident for at least five consecutive years to be may be able to access for Medicare. If you have been a green card holder for five years or more, you can enroll at 65 the same way a citizen does. Bring your green card and proof of the five-year residency when you enroll.

Can I enroll in Medicare before I turn 65 if I am still working?

No, unless you are on SSDI or have end-stage renal disease. If you have group health insurance through your job, you can delay Part B enrollment without penalty, but you cannot start Medicare before 65 just because you want to. You must wait until your 65th birthday or until you have been on disability for 24 months.

What if I was born on the first day of the month?

Your Medicare coverage starts the month before you turn 65. Your Initial Enrollment Period opens three months before that month. For example, if you were born January 1, your coverage starts December 1, and your enrollment window opens September 1.

Do I have to enroll in all four parts of Medicare?

No. Part A (hospital) is automatic for most people and has no monthly cost. Part B (doctor visits) is optional but recommended; if you delay it without a may have access to reason, you pay a penalty. Part D (prescription drugs) is optional but carries a penalty if you go without coverage and enroll later. Part C (Medicare Advantage) is an alternative to Parts A and B, not an addition.

What if I am not sure whether I am a permanent resident or just have a work visa?

Contact U.S. Citizenship and Immigration Services (USCIS) or your immigration attorney to confirm your status. Only permanent residents (green card holders) who have lived in the U.S. for five consecutive years are may be able to access for Medicare. If you have a work visa, you are not may be able to access, even at 65.