Already Enrolled in Medicare

If you are already enrolled in Medicare Part A and you want to enroll in Part B, please complete form CMS-40B, Application for Enrollment in Medicare – Part B (medical insurance). If you are applying for Medicare Part B due to a loss of employment or group health coverage, you will also need to complete form CMS-L564, Request for Employment Information.

You have three options to submit your enrollment request under the Special Enrollment Period. 
You can do one of the following:

  1. Go to “Apply Online for Medicare Part B During a Special Enrollment Period” and complete CMS-40B and CMS-L564. Then upload your evidence of Group Health Plan or Large Group Health Plan.
  2. Fax your forms to 1-833-914-2016.
  3. Mail your CMS-40BCMS-L564, and evidence to your local Social Security field office.

Note: When completing the CMS-L564:

Source: https://www.ssa.gov/benefits/medicare/