The Basic Rule: Age 65 or Older, or Certain Disabilities

You become covered by Medicare Part A and Part B automatically when you turn 65, as long as you or your spouse paid Medicare taxes while working. You do not have to do anything — Social Security will enroll you. Part A covers hospital stays, skilled nursing care, and hospice. Part B covers doctor visits, outpatient care, and medical equipment.

If you are younger than 65, you may still be covered if you have been receiving Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). These are the only disability pathways to Medicare before 65.

If you are not a U.S. citizen, you must have been a permanent resident for at least five years to be covered at 65. Undocumented immigrants do not may have access to for Medicare Part A or Part B under any circumstance.

Key Takeaways

  • You may have access to for Medicare Part A and Part B at age 65 if you or your spouse paid Medicare taxes for at least 10 years (40 quarters) while working.
  • You become enrolled automatically three months before your 65th birthday; you do not need to sign up yourself.
  • If you are under 65, you may may have access to through SSDI (after 24 months), ESRD, or ALS diagnosis.
  • If you delay enrolling in Part B after age 65 without a valid reason, you will pay a permanent penalty on your premium.
  • Permanent residents must have lived in the United States for at least five years to may have access to at 65.

The Work History Requirement: 40 Quarters of Medicare Tax

To may have access to for Part A at 65, you need 40 quarters of Medicare tax contributions. A quarter is three months. This means you need roughly 10 years of work history, though the years do not have to be consecutive. If you worked part-time or had gaps in employment, the quarters still count as long as you paid into Medicare.

Your spouse's work history can also may have access to you. If your spouse paid Medicare taxes for 40 quarters, you become covered at 65 even if you never worked or worked fewer than 10 years. You do not need to be married now — if you were married for at least 10 years and are now divorced, you can still use your ex-spouse's work record.

If you do not have 40 quarters yourself and do not have a spouse or ex-spouse with 40 quarters, you cannot get Part A at 65. Some people in this situation can buy Part A by paying a monthly premium, but this is uncommon and costs more than standard Part A.

When You Turn 65: Automatic Enrollment and Timing

Social Security automatically enrolls you in Part A and Part B three months before your 65th birthday. Your Medicare card will arrive in the mail about two weeks before your coverage starts. You do not have to call anyone or fill out forms — the system does this based on your Social Security record.

Your coverage begins on the first day of the month in which you turn 65. If your birthday is January 15, your coverage starts January 1. If your birthday is January 1, your coverage still starts January 1.

If you are still working at 65 and have health insurance through your employer, you can delay Part B enrollment without penalty as long as your employer has 20 or more employees. You must enroll within eight months of leaving that job or losing the coverage. If you miss this window, you will pay a permanent 10 percent penalty on your Part B premium for each year you were late.

Disability Before 65: SSDI, ESRD, and ALS

If you receive Social Security Disability Insurance (SSDI), you become covered by Medicare Part A and Part B automatically after you have been on SSDI for 24 months. The 24 months starts from the month you began receiving SSDI payments, not from the month you applied. You do not need to reach any age threshold.

If you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or transplant — you become covered when ready upon diagnosis or when dialysis begins, whichever comes first. You do not need to be on SSDI or have any work history. Part A covers dialysis and transplant-related care; Part B covers doctor visits and outpatient services.

If you are diagnosed with amyotrophic lateral sclerosis (ALS), you become covered by Medicare when ready. You do not need to wait for SSDI approval or have any work history. This is the only condition that triggers when ready Medicare coverage without a waiting period.

Citizenship and Residency Requirements

You must be a U.S. citizen or a permanent resident to may have access to for Medicare at 65. If you are a permanent resident, you must have held that status for at least five consecutive years. The five years must be completed before you turn 65.

If you are a permanent resident who has not yet completed five years, you will not be enrolled in Medicare at 65. You become covered on the date you complete five years of permanent residency, even if that is after your 65th birthday.

If you are a citizen of another country on a visa (such as a work visa or student visa), you do not may have access to for Medicare. Undocumented immigrants do not may have access to under any circumstance, regardless of age, work history, or medical condition.

What Happens If You Do Not may have access to

If you reach 65 and do not have 40 quarters of work history, and you do not have a spouse or ex-spouse who does, you will not be automatically enrolled in Medicare Part A. Social Security will send you a notice explaining this. You can still purchase Part A by paying a monthly premium, though the cost is higher than it would be if you had may have access to through work history.

If you are under 65 and do not have SSDI, ESRD, or ALS, you do not may have access to for Medicare. You would need to purchase private health insurance through your employer, the individual market, or a program like Medicaid (which has different rules and income limits).

If you are a permanent resident who has not completed five years, you should contact Social Security three months before you complete the five-year mark to confirm your enrollment will begin on schedule. Bring proof of your permanent residency date.

Questions to Ask Your Doctor or Social Security

Ask your doctor: "Will my condition (ESRD, ALS, or disability) make me may be able to access for Medicare before 65?" This matters because your doctor may need to document your diagnosis or refer you to Social Security for SSDI.

Ask Social Security: "How many quarters of Medicare tax do I have on my record?" You can request a Statement of Earnings online at ssa.gov or by calling 1-800-772-1213. This tells you whether you meet the 40-quarter requirement.

Ask Social Security: "If I delay Part B after 65, will I owe a penalty?" This matters if you plan to stay on employer coverage past 65. Get the answer in writing so you have proof if a penalty is later assessed incorrectly.

Frequently Asked Questions

Can I use my ex-spouse's work record if we have been divorced for more than 10 years?

Yes. As long as you were married for at least 10 years and are now unmarried, you can use your ex-spouse's work record to may have access to for Part A at 65. You do not need their permission. Your ex-spouse does not need to be receiving Social Security themselves.

What if I worked outside the United States?

Work done outside the U.S. generally does not count toward the 40-quarter requirement, even if you paid taxes. However, some countries have agreements with the U.S. that allow certain work to count. Contact Social Security to ask whether your specific work history qualifies.

Do I have to enroll in Part B if I am still working at 65?

No, if your employer has 20 or more employees and you are covered by their health plan. You can delay Part B without penalty. However, you must enroll within eight months of leaving that job or losing coverage, or you will pay a permanent penalty.

If I am on SSDI, when exactly does Medicare start?

Medicare begins on the first day of the 25th month you receive SSDI. If you started SSDI in January 2023, your Medicare coverage begins January 1, 2025. Social Security will send you a Medicare card automatically; you do not need to do anything.

What if Social Security says I do not have 40 quarters — can I appeal?

Yes. If you believe Social Security's count is wrong, you can request a detailed Statement of Earnings and ask them to review it. Bring any old pay stubs or W-2 forms you have. If you still disagree, you can file a formal appeal with Social Security.