Form details
Form CMS-40B
Medicare Part B Enrollment
Agency: Centers for Medicare & Medicaid Services / Social Security Administration
Source checked 6 September 2026. Appears to be the current published version.
Form information
What this process is for
Used to enroll in Medicare Part B, including for people who delayed enrollment while covered through an employer.
- Online application
- Some enrollments can be completed online through Social Security.
- Save and resume
- The printed form has no save step; a guided experience can pause and resume.
- Where to ask for help
- You may want to confirm with the Social Security Administration.
- Official source
- ssa.gov