If you’re over 65 and leaving employment or ending your employer/spouse’s group health plan, you’ll need to complete two forms to enroll in Medicare Part B using the Special Enrollment Period (SEP).

Note: If you already have both Medicare Part A and Part B, no further action is needed at Social Security.

Two Required Forms

Form 1: CMS-40B (You complete and sign)

• Who fills it out: You (the Medicare beneficiary)
• Key requirement: In the Remarks section, enter your requested Medicare start date
• Start date format: Always the first day of a month (April 1, 2025 or May 1, 2025)
• Timing: You can apply up to 90 days before your requested effective date

Form 2: CMS-L564 (Employer completes and signs)

• Who fills it out: A representative from your employer
• Purpose: Confirms your group health coverage details

Important: For couples, use separate forms for each person.

How to Apply

Step 1: Have both forms completed and signed before applying

Step 2: Apply for Medicare online at ssa.gov/benefits/medicare

• Be sure to apply for both Part A and Part B
• You can now complete this process entirely online (previously required in-person or mail submission)

Step 3: Submit your two completed forms

How to Submit Your Forms

Best Option: Upload both forms when applying online 

Alternative Options:

• In person: Visit your local Social Security office
• Mail: Send to your local Social Security office
• Fax: Fax to your local Social Security office

Important Notes

• Phone contact: Social Security may call you after you apply online. Since employees may work from home, your caller ID might not show “Social Security.” For security, ask the caller to confirm the date you applied online.
• Questions? Contact Social Security at 800-772-1213

Remember: This process is for enrolling in Medicare Part B after your Initial Enrollment Period (the 3-month period following your 65th birthday month) when you’ve been covered by employer/union group insurance since age 65.