Enrolling in Medicare B (already enrolled in Part A)

Medicare Part B Enrollment Instructions

How to Enroll in Medicare Part B (If You Already Have Part A)

Who This Applies to

You already have Medicare Part A and need to enroll in Part B.

Step 1: Have Your Employer Complete the Employment Information Form

Download the Request for Employment Information Form
- - Give this form to the employer that provides/provided your health insurance coverage.

📌 Important:

- If both you and your spouse are applying for Medicare, each of you must submit your own completed form.
- The form must be filled out by the employer that provided the health insurance coverage
- See the section below for guidance on how to fill out this form correctly.

Step 2: Complete the Medicare Part B Application

Complete the CMS-40B Application for Enrollment in Medicare Part B
In Section 2 you will be asked to choose your Medicare Part B coverage start date.
- We recommend writing the month and year you want your Part B coverage to begin.

A separate application must be completed for each person applying for Medicare.

Step 3: Submit Both Forms Through SSA.gov

Once both forms are completed:

1. Request for Employment Information
2. CMS-40B Application for Enrollment in Medicare Part B

You will need to sign in to your SSA.gov account and upload both documents.

After signing in:

1. Follow the prompts to upload your completed forms.
2. Review your submission carefully.
3. Submit the documents through SSA.gov.

After You Apply

1. Save your confirmation page— it’s your proof of submission.
2. Regularly log in to mySSA.gov to track the status.
3. If Medicare Part B doesn’t appear in your account before your requested effective date, contact your local Social Security office to confirm they received your application.

Request for Employment Information Form

Frequently Asked Questions

Who needs to complete the employment form?
Take the form to your (or your spouse’s) Human Resources or Benefits Department for completion.

A separate form is needed for each spouse applying for Medicare.

The employer must be the one that provided the group health coverage — even if that’s not the current or shared employer.
What is the purpose of the employment form?
The purpose of the form is to verify you have had other, creditable coverage since becoming Medicare eligible at 65. The form confirms:

The dates you (or your spouse) were actively employed.

The start date of your group health plan coverage.

🔍 Important: The coverage start date should reflect your original enrollment in employer-sponsored health insurance — not a later reenrollment date.
I've had multiple employers since turning 65
I can't get the form signed

Other Ways to Apply (If you can't apply online)

Apply by Fax
To apply by fax, you’ll need to complete two forms:

CMS-40B – Medicare Part B Application

CMS-L564 – Request for Employment Information

Important Note for Your Application

On the CMS-40B form, in the Remarks/Comments section, write: “I would like my Medicare Part B to begin __/01/202_.” This helps ensure your enrollment starts on the correct date.

Submitting Your Forms

Fax both completed forms to your local Social Security Field Office.

Use this link to find your local office’s fax number and phone number.

We strongly recommend calling the field office about 3 business days after faxing to confirm they received your documents.
Apply by Mail
To apply by Mail, you’ll need to complete two forms:

CMS-40B – Medicare Part B Application

CMS-L564 – Request for Employment Information

Important Note for Your Application

On the CMS-40B form, in the Remarks/Comments section, write: “I would like my Medicare Part B to begin __/01/202_.” This helps ensure your enrollment starts on the correct date.

Submitting Your Forms

Mail your forms to your local Social Security field office (look up address with this link)

⚠️ Timing Warning:
We do not recommend using this option if you are within 30 days of your requested Medicare Part B start date.

If you don’t receive confirmation that your application is being processed before your requested effective date, please contact your local Social Security field office to verify they have received it.
Apply in Person
Currently many Social Security Offices are not accepting in person visits.

Check with your local Social Security field office

Complete forms CMS-40B (Part B Application) and CMS-L564 (Request for Employment Information)

In the notes/comments section of the Part B application please write: “I would like my Medicare Part B to begin ___/01/202___.”

Medicare Part B Enrollment Instructions

How to Enroll in Medicare Part B (If You Already Have Part A)

Who This Applies to

Step 1: Have Your Employer Complete the Employment Information Form

Step 2: Complete the Medicare Part B Application

Step 3: Submit Both Forms Through SSA.gov

After You Apply

Request for Employment Information Form

Frequently Asked Questions

Other Ways to Apply (If you can't apply online)

To apply by fax, you’ll need to complete two forms:

Submitting Your Forms

To apply by Mail, you’ll need to complete two forms:

Submitting Your Forms

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