How and when do I enroll in Medicare?

This newsletter will provide information on enrolling in Medicare, with detailed instructions for completing an enrollment during a Special Enrollment Period (SEP).  You are automatically enrolled in Medicare Parts A and B at age 65 if you begin getting benefits from Social Security or Railroad Retirement Board before your 65th birthday; or you have reached the 25th month of being deemed disabled.    Otherwise, you must facilitate your own enrollment.  You have the choice to enroll in Medicare when you have an End Stage Renal Disease diagnosis. 

For most people, the first opportunity to enroll in Medicare Parts A and B would be when you turn 65 years of age. This would be your Initial Enrollment Period (IEP).  Your IEP begins three months before the month when you turn 65, and continues through the month when you turn 65, and three months after the month when you turn 65.   It is a seven-month window allowing you to enroll without penalty.  If you enroll in Medicare during the first three months of your IEP, your coverage will be effective the first of the month when you turn 65.  If you enroll in any of your other IEP months, coverage will begin the first of the following month.  You will pay no premium for Part A if you or your spouse paid Medicare taxes for 40 quarters, or more.  Part B will have a monthly premium. Apply online at or by calling Social Security at 1-800-772-1213.

If you will have continued coverage past your IEP by your, or your spouse’s Employer Group Health Plan (EGHP), with more than 20 employees, based on active employment, you can delay enrollment in Medicare because the EGHP will continue to be your primary coverage. However, if you are eligible for “free” Part A, it would be to your advantage to enroll in Part A during your IEP.  Since Part B has a premium, you may want to delay this enrollment until your, or your spouse’s employment ends.  Your EGHP will be your primary coverage, with Medicare Part A secondary.  If the EGHP has fewer than 20 employees, Medicare will be your primary coverage and the EGHP will be secondary.  In this case, you should not delay Medicare enrollment; you need both parts of Medicare to be fully covered. The end of the EGHP triggers an eight-month Special Enrollment Period (SEP) to enroll in Medicare.  Enrollment at this time, adding Part B, is easier if you enrolled in Part A during your IEP.

If you already have a Medicare card with an effective date for Medicare Part A, the process for online enrollment in Medicare Part B has recently been simplified by the Social Security Administration.  You need two forms for Part B enrollment.  At the bottom of the home page, click on the word “Forms”.  This is a listing of all the forms available from SSA.   You will need to find form CMS 40B (which is fifth on the list) and CMS L564 (sixth on the list).  If you wish to enroll online, download CMS L564 and save it in your document file.    This form is used to verify your continuous employment and must be completed by your employer.  Send form CMS L564 electronically to your employer to be completed by the HR department and returned to you electronically.  Save it in your document file.  Once you have done this, the form will be ready to upload into your online Part B application when you get to that part of the application.   The form CMS 40B is already embedded in the online application.   You will complete the information on form CMS 40B.  Here are step-by-step instructions for online and manual enrollment.  

Online enrollment for Medicare Part B:

  • Go to  
  • Click on “Sign up for Part B only”
  • Click on "Start application”
  • Once the application is on your screen, click “continue”
  • Work through the application which begins with form CMS 40B and progresses to the point where you must upload some type of employment verification.  The uploaded form CMS L564 will be that verification.  If, for some reason, you are not able to provide CMS L564, the form instructions list other accepted types of employment verification.
  • In section A7 be sure to enter when you want Part B to begin

Enrolling in Medicare Part B Manually 

  • Go to Homepage
  • Locate and print Forms CMS 40B and CMS L564
  • Complete CMS 40B yourself, indicating in the “remarks” section, when you want Part B to begin    
  • Ask your employer to complete CMS L564 to verify your continuous employment
  • When both forms are completed, mail or fax them to your local SSA office (remembering to keep a copy of the forms and get a receipt at the post office if you mail them).  It may be possible to personally deliver them to the local SSA office if the office is open to the public.
  • If West Chester SSA office is your local office, the mailing address is:

            1101 West Chester Pike, West Chester, PA 19382

            Fax #:  1-833-787-1782

  • If you are doing applications for you and your spouse, make sure you each have these forms and send each spouse’s documents separately

Once you receive a new Medicare card with effective dates for Part A and Part B indicated on the card, you can enroll in a Medicare Advantage Plan or a Medigap.  If you choose Original Medicare, alone, or with a Medigap, prescription coverage is delivered by a stand-alone Part D Plan.  If you choose a Medicare Advantage Plan, it should include prescription coverage, unless you have other creditable coverage, such as VA, retiree, or PACE prescription coverage.  You have two months from the end of your EGHP to add prescription coverage without incurring a penalty and a delay in the start of coverage. Enrollment in a Part D plan can be facilitated when one, or both parts of Medicare are effective.  The Part D plans can become effective the first of the month after you apply.  

If you do not enroll during your IEP and you do not qualify for an SEP, you will have to wait for the Annual General Enrollment Period (GEP) from January 1 – March 31.  This enrollment will be completed by phone with SSA.  You may have to pay a penalty for delayed enrollment.

Some of these rules will be different if you do not qualify for free Part A.  A PA MEDI counselor can explain these situations to you.

Contact PA MEDI to talk to a counselor if you need more information on either of these enrollment periods, or if you have other Medicare-related questions.  PA MEDI is Pennsylvania’s program of free insurance consultation under the auspices of the Department of Aging.    Call our Helpline 610-344-5004, Option 2, and leave a message; or send an email to [email protected].  


Show All Answers

1. What is Medicare's Annual Open Enrollment Period?
2. How and when do I enroll in Medicare?
3. How does Medicare work with employer based insurance?
4. Am I covered by Medicare if my spouse or I is employed?
5. When can I switch my Medicare plan?
6. Does Medicare Cover COVID-19 Costs?
7. Do I need Medicare Part D?
8. Does Medicare cover vaccines?
9. What if one or more of my drugs is no longer covered by my Medicare drug plan?
10. What happens if you lose your Employer Group Health Plan when you are eligible for Medicare?
11. What's new for 2023?
12. When are the Medicare General Enrollment Period and the Medicare Advantage Open Enrollment Period?
13. How do I avoid Medicare scams?
14. What are 5-Star plans and when can I enroll?
15. How can I get help paying for Medicare Part B and Part D?
16. What are the different parts of Medicare?
17. How do I update my contact information if I'm moving?
18. Can I change my Medicare Advantage or Medicare Prescription Drug Plan anytime?
19. How do I create a Medicare account?
20. What are the benefits of the Inflation Reduction Act (IRA) of 2022 for Medicare beneficiaries?