Who Needs to Fill Out Medicare Forms CMS-L564 & CMS-40b? 

The CMS-L564 and CMS-40b are only for individuals who are enrolling in Medicare and are 65 years and four months old (or older). In other words, they didn’t enroll in Medicare during the initial enrollment period when they turned 65. The most common reason people don’t enroll in Medicare when they turn 65 is that they or their spouse is still working. Now they’ve retired and want to enroll in Medicare. But since they missed their initial enrollment period when they turned 65, they will have to fill out the CMS-L564 and CMS-40b to avoid Medicare penalties. 

For those of you enrolling in Medicare when you’re first eligible at 65, you will not need to worry about filling out the forms. In fact, enrolling in Medicare when you turn 65 is a simple process that can be done entirely online. 

How to Fill Out Medicare Form CMS-L564: Request for Employment Information

CMS-L564: Section A

The CMS-L564 is called a request for employment information. You are responsible to fill out Section A of this form with your employer’s name and address. The purpose of this form is to verify that you’ve been employed and had employer coverage from the time you turned 65 to enrollment in Medicare. This means you are required to provide the information for every employer you’ve had since you turned 65. So if you had two employers since turning 65, make sure to fill out two CMS-L564 forms.

CMS-L564: Form for Spouse

If you retired at 65 but waited to enroll in Medicare because your spouse was still working (meaning you were covered by their work insurance), you will fill out the form a little differently. Instead of placing your name in both the employee and applicant lines, you will list your spouse as the employee and place your name in only the applicant line. 

CMS-L564: Section B

Your employer is responsible for filling out Section B of the CMS-L564 form. Although it’s not up to you to fill out this section, you do need to understand several key items within it to ensure the form is filled out correctly. 

Question #1 asks, “Is the applicant covered under an employer group plan?”  If you’re covered by a group plan at work, make sure your employer answers “yes.” Being covered by a group plan is the only thing that makes you eligible to come into Medicare with no penalties or problems. 

If your employer answers “Yes” to question #1, they will then have to provide the date your employer coverage began. Many H.R. departments make the mistake of thinking the question is asking when the group plan’s current insurance provider (Aetna, United Health Care, etc.) began covering the group. This is not the date Medicare is looking for. Instead, Medicare wants to know how long you’ve been covered by your employer group plan, regardless of the insurance carrier. Typically, this date coincides with the day you started working at the company. 

Finally, your employer will indicate whether your coverage has ended or not. If your coverage has ended, they will provide the date it ended. This date is very important because you only have eight months after the day your employer coverage ends to enroll in Medicare. If you wait longer than eight months, you’ll miss the special enrollment period and be subject to penalties. 

Once Section B is filled out, a company official from your employer will sign and date the document. 

How to Fill Out Medicare Form CMS-40b

The CMS-40b is a simple form indicating when you want to start your Medicare Part B coverage. It should only take about one minute to complete. First, you’ll need to provide your Medicare number. If you’ve already applied for Medicare A and B, but don’t have your Medicare number yet, you can find your Medicare number online by going to SSA.gov. Keep in mind, you’ll have to wait about one week after applying before accessing your Medicare number online. If you’re not able to find your number online, you can wait until your Medicare card comes in the mail (usually it comes within one month of enrolling). 

You’ll then fill in your last name, first name, middle initial, mailing address, and phone number. Down near the bottom, you’ll see a “remarks” section. This is the most important part of the CMS-40b form. In the remarks section, you will pick the date you want to start your Medicare coverage.  Let’s say your group plan at work ends on August 31st. You will want to start Medicare coverage on September 1st. If you don’t write a start date on the form, your Medicare coverage will automatically start the month after Medicare receives your CMS-40b form. 


If you are enrolling in Medicare after the initial enrollment period when you turned 65, you will have to fill out the CMS-L564 and the CMS-40b forms to avoid Medicare penalties. If you want help enrolling in Medicare or would like assistance filling out these forms, visit MedicareSchool.com to work with one of our free guides. 


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