The Basic Rules for Medicare Enrollment

You can enroll in Medicare if you are 65 or older, or if you are under 65 and have received Social Security Disability Insurance (SSDI) for at least 24 months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). Most people become may be able to access the month they turn 65. If you are a U.S. citizen or permanent resident who has lived in the country for at least five years, you meet the residency requirement.

You do not have to be retired to enroll in Medicare at 65. You can still be working and earning income. However, if you claim Social Security retirement benefits before your full retirement age, your benefit amount will be permanently reduced — this is separate from Medicare enrollment and is a Social Security decision, not a Medicare one.

Key Takeaways

  • You become may be able to access for Medicare the month you turn 65, regardless of whether you are still working.
  • People under 65 can enroll if they have received SSDI for 24 months, or if they have ESRD or ALS.
  • You must be a U.S. citizen or permanent resident who has lived in the country for at least five years.
  • Your enrollment window opens three months before the month you turn 65 and closes three months after — missing it can mean a permanent penalty on your premiums.

Enrollment Windows and important date

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65, includes 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 any time during this window without penalty.

If you miss your Initial Enrollment Period, you can still enroll during the General Enrollment Period, which runs January 1 through March 31 each year. However, coverage does not start until July 1 of that year, and you will pay a permanent 10 percent premium increase for each year you delayed enrollment. This penalty stays with you for life, so enrolling late is costly.

If you are still working at 65 and your employer has 20 or more employees, you may be able to delay enrollment without penalty through your employer's health plan. You will need to show proof of employer coverage when you do enroll. Talk to your employer's benefits office about whether this applies to you.

Special Situations: Under 65 and SSDI

If you receive SSDI, you become may be able to access for Medicare automatically after you have been on SSDI for 24 months. You do not need to explore separately — Social Security will enroll you. Your Medicare coverage typically begins the first day of the 25th month of your SSDI may be able to access. You will receive your Medicare card in the mail before coverage starts.

If you receive Supplemental Security Income (SSI) instead of SSDI, you do not automatically may have access to for Medicare based on SSI alone. However, if you also have SSDI, the 24-month rule applies. Contact Social Security to confirm your situation if you are unsure which program you receive.

End-Stage Renal Disease and ALS

If you have end-stage renal disease (ESRD) — kidney failure requiring dialysis or a transplant — you become may be able to access for Medicare regardless of age. Your may be able to access begins the first day of the month in which your dialysis treatment starts, or the month of your transplant. You do not have to wait for a waiting period.

If you have amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's disease), you become may be able to access for Medicare when ready upon diagnosis. Unlike SSDI, which requires a 24-month waiting period, ALS qualifies you right away. You will need to provide medical documentation of your diagnosis when you enroll.

Citizenship and Residency Requirements

You must be either a U.S. citizen or a lawful permanent resident (green card holder) to enroll in Medicare. If you are a permanent resident, you must have lived in the United States for at least five consecutive years. Time spent outside the country can interrupt this requirement, so if you have traveled or lived abroad, contact Social Security to confirm your residency status before enrolling.

If you are a citizen living abroad, you can still enroll in Medicare at 65, but your coverage options are limited. Original Medicare (Parts A and B) has limited coverage outside the U.S., and most Medicare Advantage plans do not cover care received outside the country. If you plan to live abroad, speak with a Medicare counselor about your options before enrolling.

What Happens After You Enroll

Once you enroll, you will receive a Medicare card in the mail within two to three weeks. Your coverage typically begins on the first day of the month you turn 65 (or the first day of the month your SSDI may be able to access reaches 24 months). You can start using your Medicare card as soon as you receive it.

After enrollment, you will need to decide whether to stay with Original Medicare (Parts A and B) or switch to a Medicare Advantage plan (Part C). You will also need to decide whether to add prescription drug coverage (Part D) and supplemental coverage. These decisions can be made during your Initial Enrollment Period or during the annual Open Enrollment Period (October 15 through December 7 each year).

Common Reasons People Are Not may be able to access

You cannot enroll in Medicare if you do not meet the age or medical requirements, and you do not have a valid Social Security number. If you are under 65 and do not have SSDI, ESRD, or ALS, you will need to wait until 65 or until you meet one of the other conditions. There is no way to enroll early based on income, health status, or other factors.

If you are not yet a permanent resident or have not lived in the U.S. for five consecutive years, you are not may be able to access. Some people in this situation may be able to purchase individual health insurance through the Health Insurance Marketplace instead. Contact your state's health insurance marketplace to learn what options are available to you.

Frequently Asked Questions

What if I turn 65 but am still working and have health insurance through my job?

You can delay enrolling in Medicare without penalty if your employer has 20 or more employees and you are covered under the employer's health plan. When you do enroll, bring proof of your employer coverage. If your employer has fewer than 20 employees, you should enroll in Medicare at 65 even if you have employer coverage, because Medicare becomes your primary payer.

Can I enroll in Medicare if I am not a U.S. citizen?

You must be a U.S. citizen or lawful permanent resident who has lived in the country for at least five consecutive years. If you are not yet a permanent resident, you cannot enroll in Medicare. You may be able to purchase health insurance through your state's Health Insurance Marketplace or through a private insurer instead.

What if I miss my enrollment window?

You can still enroll during the General Enrollment Period (January 1 through March 31), but coverage will not start until July 1, and you will pay a permanent 10 percent premium increase for each year you were late. If you have a may have access to life event (such as losing employer coverage), you may be able to enroll outside these windows without penalty — contact Social Security to ask.

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

If you are covered under an employer health plan with 20 or more employees, you can delay Part B enrollment without penalty. However, you must enroll in Part A (hospital insurance) at 65. When you do enroll in Part B later, bring proof of your employer coverage to avoid the late-enrollment penalty.

How do I know if I have been on SSDI for 24 months?

Social Security will notify you when you become may be able to access for Medicare based on SSDI. You will receive a notice in the mail and your Medicare card will be sent automatically. If you do not receive notice by the 25th month of your SSDI may be able to access, contact Social Security to confirm your status.