Medicare Form CMS-40B
Apply to enroll in Medicare Part B medical insurance.
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About Medicare Form CMS-40B
Form CMS-40B, Application for Enrollment in Medicare Part B (Medical Insurance), is used by people who already have Medicare Part A and want to sign up for Part B. It is often used by people who delayed Part B and are now enrolling, such as during a special enrollment period after losing job-based coverage. You give your Medicare number and basic information and choose when you want your coverage to begin.
This page is a general guide and a fillable helper, not medical or insurance advice. Always download and file the current official form from Medicare at https://www.medicare.gov/ and the official CMS-40B page, and confirm the fields, enrollment periods, and instructions match before you sign.
Who needs to complete it
- People who have Medicare Part A and want to enroll in Part B.
- Individuals who delayed Part B and are now signing up.
- People enrolling during a special enrollment period, such as after job-based coverage ends.
- Anyone directed to use CMS-40B to add Part B medical insurance.
How to fill out Medicare Form CMS-40B
- 1Enter your name as it appears on your Medicare card.
- 2Enter your Medicare number exactly as shown on the card.
- 3Provide your mailing address and telephone number.
- 4Indicate when you want your Part B coverage to start, following the choices on the form.
- 5Answer the remarks or eligibility questions if the form asks them.
- 6If you had group health coverage based on current employment, complete the related section as instructed.
- 7Sign and date the application.
- 8Submit it to Social Security using the method described in the current instructions.
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Frequently asked questions
Who uses Form CMS-40B?
It is generally used by people who already have Medicare Part A and want to enroll in Part B. Many people use it when signing up after a delay. This is a general guide, not medical or insurance advice.
When can I enroll in Part B?
Medicare has specific enrollment periods. When you can sign up and when coverage starts depend on your situation. Check the current official Medicare guidance before you file.
Where do I send the form?
CMS-40B is generally submitted to Social Security, which handles Medicare enrollment. Follow the current instructions for the correct submission method.
Is this the official Medicare form?
This is a fillable helper to make completion easier. Always download and file the current official form from Medicare at https://www.medicare.gov/ and confirm the fields match.