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Original Medicare (Part A and B) Eligibility and Enrollment

Medicare Hospital Insurance (Part A), as well as Medicare Supplementary Medical Insurance (Part B) is available to three basic groups of "insured" individuals-the aged (although certain aged individuals can qualify for Part A without being "insured"), the disabled, and those with End-Stage Renal Disease (ESRD).  

Medicare Part A

To be eligible for premium-free Part A, an individual must first be "insured" based on their own earnings or those of a spouse, parent, or child.  To be insured, the worker must have a specified number of quarters of coverage (QC's) the exact number required is dependent on whether the person is filing for Part A on the basis of age, disability, or ESRD.  QC's are earned through payment of payroll taxes under the Federal Insurance Contributions Act (FICA) during the person's working years.  Most individuals pay the full FICA tax so the QC's they earn are usable to insure them for both monthly social security benefits and Part A.  However, certain Federal, State, and local government employees pay only the Part A portion of the FICA tax.  The QC's they earn can be used only to insure them for Part A; they may not be used to insure them for monthly social security benefits.  

Aged Insured Individual

To be eligible for premium-free Part A on the basis of age, a person must be age 65 or older and either eligible for monthly social security or railroad retirement cash benefits, or would be eligible for such benefits if the worker's QC's from government employment were regular social security QC's.  An individual who is insured for monthly benefits need not actually file an application to receive the benefits.  If such a person continues to work beyond age 65, he or she may instead elect to file an application for Part A only.  Part A for the aged begins with the month in which the individual becomes age 65*, provided he or she files an application for Part A or for cash benefits and Part A within 6 months of the month in which he or she becomes age 65.  If the application is filed later than that, Part A entitlement can be retroactive for only 6 months.  

* For Medicare purposes, individuals attain age 65 the day before their actual 65th birthday and Part A is effective on the first day of the month upon attainment of age 65.  For an individual whose 65th birthday is on the first day of the month, Part A is effective on the first day of the month preceding their birth month.  For example, if an individual's birthday is on December 1, Part A is effective on November 1 since for Medicare purposes, he or she attained age 65 on November 30.  

Aged Uninsured Individual

A second group of aged individuals who are eligible for Part A are those persons age 65 or over who are not insured but elect to purchase Part A coverage by filing an application at a social security office.  Because a monthly premium is required, this is called "Premium-Part A".  (For a detailed explanation of the Monthly Premium, click on the link beneath the heading entitled Medicare Monthly Premium that's located in the Related Links Outside CMS section).  In addition to the application and monthly premium requirements, an individual must be a U.S. resident and either a citizen, or an alien lawfully admitted for permanent residency who has resided in the U.S. continuously for at least 5 years as of the time the application is filed.  persons desiring Premium-Part A can only file for coverage during a prescribed enrollment period (see the discussion under Medicare Part B) and must also enroll or already be enrolled in Part B.  

Premium-Part A ends if one of the following occurs: 

  • A voluntary request;
  • Nonpayment of Part A premiums; 
  • End of entitlement to Medicare part B; or 
  • Death.

Disabled Individual

A disabled person who is entitled to social security or railroad retirement benefits on the basis of disability is automatically entitled to Part A after 24 months of entitlement to such benefits.  In addition, disabled persons who are not insured for monthly social security disability benefits but would be insured for such benefits if their QC's from government employment were social security QC's, are deemed to be entitled to disability benefits and automatically entitled to Part A after being disabled for 29 months.  

Part A entitlement on the basis of disability is available, not only to the worker, but also to the widow, widower or child of a deceased, disabled or retired worker if any of them become disabled within the meaning of the Social Security or Railroad Retirement Acts.  Beginning July 1, 2001, individuals whose disability is Amyotrophic Lateral Sclerosis (ALS) are entitled to Part A the first month they are entitled to Social Security disability cash benefits.

End-Stage Renal Disease (ESRD)

Individuals are eligible for Part A if they receive regular dialysis treatments or a kidney transplant, have filed an application, and meet one of the following conditions:

  • have worked the required amount of time under Social Security, the Railroad Retirement Board, or as a government employee; or 
  • are getting or are eligible for Social Security or Railroad Retirement benefits; or 
  • are the spouse or dependent child of a person who has worked the required amount of time under Social Security, the Railroad Retirement Board, or as a government employee; or 
  • are getting Social Security or Railroad Retirement benefits.  

Part A coverage begins: 

  • the 3rd month after the month in which a regular course of dialysis begins; or 
  • the first month in which a regular course of dialysis begins of dialysis if the individual engages in self-dialysis if the individual engage in self-dialysis training; or
  • the month of kidney transplant;
  • two months prior to the month of transplant if the individual was hospitalized during those earlier months in preparation for the transplant.  

Medicare Part B 

Individuals residing in the United States (except residents of Puerto Rico) who become entitled to premium-free Part A are automatically enrolled in Part B.  Since Part B is voluntary program which requires the payment of a monthly premium, those individuals who do not want coverage may refuse enrollment.  (For a detailed explanation of the Monthly Premium, click on the the link beneath the headings entitled Medicare Monthly Premium and Medicare Part B Premium Information that are located in the Related Links Outside CMS section).   

A person age 65 or over who is not entitled to premium-free Part A must meet the following requirements to be entitled to Part B: he or she must be a U.S. resident and either a citizen, or an alien who has been lawfully admitted for permanent residence with 5 years continuous residence in this country at the time of filing.  Individuals who are not eligible for automatic enrollment, or who previously refused Part B, or who terminated their Part B enrollment, may enroll (or re-enroll) in Part B only during prescribed enrollment periods.  

Enrollment Periods

Individuals who want Premium-Part A and/or Part B may only enroll during prescribed enrollment periods.  There are four enrollment periods that apply to both Premium-Part A and Part B: the initial enrollment period, the general enrollment period, the special enrollment period for the working aged and the working disabled, and the special enrollment period for international volunteers. There is an additional enrollment period for Premium-Part A, the transfer enrollment period, that applies only to individuals age 65 or older who are or were enrolled in a Medicare Advantage or Medicare 1876 cost plan.  

Initial Enrollment Period (IEP)

For most individuals, the IEP begins with the first day of the third month before the month in which a person first meets the Part B or Premium-Part A eligibility requirement and ends 7 month later, e.g., the IEP for the aged begins 3 months before the individual attains age 65 and ends the third month after the month the individual attains age 65.  

General Enrollment Period (GEP)

The GEP takes place from January 1 through March 31 of each year.  Part B and Premium Part A coverage is effective July 1 of that same year.  

Special Enrollment Period (SEP) for the Working Aged and Working Disabled.  

Individuals who do not enroll in Part B or Premium-Part A when first eligible because they were covered under a group health plan based on their own or a spouse's current employment (or the current employment of a family member, if disabled) may enroll during the SEP.  The individual can enroll at anytime while covered under the group health plan based on current employment, or during the 8-month period that begins the month the employment ends or the group health plan coverage ends, whichever comes first.  Individuals with ESRD are not eligible to enroll during this.

Special Enrollment Period (SEP) for International Volunteers

Individuals who do not enroll in Part B or Premium-Part A when first eligible because they were performing volunteer service outside of the United States for at least 12 months on behalf of a tax-exempt. organization and had health insurance that provided coverage for the duration of the volunteer service may enroll during the SEP.  The individual can enroll during the 6-month period that begins the month he/she is no longer eligible for Medicare Advantage or Medicare 1876 cost plan may enroll in Premium-Part A during the TEP.  The individual may enroll during any month in which the individual is enrolled in the Medicare Advantage or Medicare 1876 cost plan or during any of the 8 consecutive months following the last month the individual was enrolled in the Medicare Advantage or Medicare 1876 cost plan.  

Termination of Enrollment

Once an individual is enrolled in Part B or Premium_Part A,coverage coverage continues until it is terminated: (1) by the individual's voluntary request; (2) because of failure to pay premiums; (3) for individuals under age 65 (disabled and ESRD), because their Part A entitlement ended (Part B terminates ad the same time as Part A; or (4) the death of the beneficiary.