When You Can Start Medicare: Age, Work History, and Other Routes

Medicare starts at 65 for most people, but you may be able to join earlier if you have a disability, end-stage renal disease, or ALS

You become may be able to access for Medicare the month you turn 65, as long as you or your spouse paid Medicare taxes while working. You do not have to stop working to enroll. The enrollment window opens three months before your 65th birthday month and closes three months after — if you miss this window, you pay a penalty on your premiums for as long as you have Medicare.

If you are under 65, you can join Medicare in three situations: you have been receiving Social Security Disability Insurance (SSDI) for 24 months, you have end-stage renal disease (ESRD) and need dialysis or a transplant, or you have been diagnosed with amyotrophic lateral sclerosis (ALS). Each route has different timing rules and different paperwork requirements.

Key Takeaways

You can enroll in Medicare starting three months before you turn 65, and you must enroll within three months after your birthday month or face a permanent penalty.
If you receive SSDI, Medicare begins automatically 24 months after your disability benefits start, with no action needed on your part.
People with end-stage renal disease can enroll in Medicare as soon as they begin dialysis or are placed on a transplant waiting list, regardless of age.
ALS patients become may be able to access for Medicare when ready upon diagnosis, without the usual 24-month waiting period that applies to other disabilities.

Enrollment at 65: The standard timeline and window

Your Initial Enrollment Period (IEP) lasts for seven months: it begins three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your window runs from March through September. You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

If you do not enroll during this window, you will pay a late enrollment penalty on your Part B premium (the medical insurance portion) for as long as you have Medicare. The penalty is 10 percent of the standard Part B premium for each full 12 months you were may be able to access but not enrolled. If you were supposed to enroll in 2020 and did not enroll until 2023, you would pay the penalty for the rest of your life.

The one exception: if you or your spouse were still working and covered by an employer health plan when you turned 65, you may have had a Special Enrollment Period that lets you enroll without penalty within eight months of losing that coverage. You will need to show proof that you had employer coverage.

SSDI recipients: Automatic enrollment after 24 months

If you receive Social Security Disability Insurance, Medicare begins automatically 24 months after your disability benefits start. You do not need to do anything — Social Security sends your Medicare card in the mail about two weeks before coverage begins. Your Medicare start date is the same regardless of your age.

The 24-month clock starts on the date Social Security approves your claim, not the date you applied or the date you became disabled. If you were approved in January 2023, your Medicare coverage begins in January 2025. If you are unsure when your benefits were approved, log into your Social Security account at ssa.gov or call 1-800-772-1213.

You will receive both Part A (hospital insurance) and Part B (medical insurance) automatically. If you want to change your coverage — for example, to add a Medigap or Medicare Advantage plan — you have a Special Enrollment Period that runs for eight months after Medicare begins.

End-stage renal disease: Enrollment tied to dialysis or transplant status

You become may be able to access for Medicare the month you begin dialysis treatment or the month you are placed on a kidney transplant waiting list, whichever comes first. Age does not matter. You must enroll yourself; Medicare does not add you automatically.

To enroll, contact Social Security at 1-800-772-1213 or visit your local Social Security office. You will need to bring proof of your ESRD diagnosis — usually a letter from your nephrologist or dialysis center stating your diagnosis and the date treatment began. Social Security will process your enrollment and send your Medicare card.

If you receive a transplant, your Medicare coverage continues for at least 36 months after the transplant, even if your kidney function improves and you no longer need dialysis. After 36 months, your coverage may end unless you meet another reason to stay on Medicare.

ALS: when ready may be able to access without the disability waiting period

Amyotrophic lateral sclerosis (ALS) is the only condition that makes you may be able to access for Medicare when ready upon diagnosis, without the 24-month waiting period that applies to other disabilities. You do not have to be receiving SSDI first.

To enroll, you must explore for SSDI through Social Security, even though you will not have to wait 24 months. Bring your ALS diagnosis letter from your neurologist to your local Social Security office, or explore online at ssa.gov. Social Security will fast-track your claim and your Medicare coverage will begin the same month your disability benefits are approved.

Because ALS progresses quickly, Social Security prioritizes these claims. Most people receive approval within weeks rather than months. Once approved, you receive both Part A and Part B automatically.

What happens if you miss your enrollment window

If you turn 65 and do not enroll during your seven-month Initial Enrollment Period, you can still enroll later during the General Enrollment Period, which runs from January 1 through March 31 each year. Coverage would begin July 1 of that year. However, you will owe the late enrollment penalty on your Part B premium for life.

The only way to avoid the penalty is to show that you had creditable coverage — employer health insurance or retiree coverage — during the time you were supposed to enroll. You must provide proof to Social Security or Medicare within a specific timeframe. If you had a gap in coverage, the penalty applies to the months you were uninsured.

Coordinating Medicare with employer coverage and retirement

If you are still working at 65 and your employer offers health insurance, you can delay enrolling in Medicare Part B without penalty, as long as your employer has 20 or more employees. Your employer coverage is considered creditable coverage. You have eight months after you leave your job or lose coverage to enroll in Part B without penalty.

Part A (hospital insurance) has different rules. If you are still working and your employer does not offer health insurance, you should still enroll in Part A at 65, even if you do not enroll in Part B. Part A is free if you or your spouse paid Medicare taxes for at least 10 years (40 quarters).

If you are self-employed or a business owner, you paid Medicare taxes on your net earnings. These quarters count toward the 40-quarter requirement. If you are unsure whether you have enough quarters, check your Social Security statement at ssa.gov or call 1-800-772-1213.

Frequently Asked Questions

What if I turn 65 outside the United States?

You can still enroll in Medicare during your Initial Enrollment Period. Contact Social Security by phone at 1-202-261-3261 (international number) or through your nearest U.S. embassy or consulate. You will need to provide proof of U.S. citizenship or permanent residency. Coverage begins the same month as for people in the U.S.

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

No, unless you meet one of the three early-enrollment conditions: you have been on SSDI for 24 months, you have end-stage renal disease, or you have ALS. If you are working and do not meet these conditions, you must wait until 65 to enroll, even if you want to.

Do I lose Medicare if I go back to work after I turn 65?

No. Once you are enrolled in Medicare, your coverage continues regardless of whether you work, how much you earn, or whether you have other insurance. You can work full-time and keep Medicare at the same time.

What if I was denied SSDI but I am still disabled?

You cannot enroll in Medicare early based on disability unless Social Security approves your SSDI claim. If your claim was denied, you can request reconsideration or appeal the decision. You must go through the Social Security appeals process; there is no other way to become may be able to access for Medicare before 65 on the basis of disability.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.