Medicare Form CMS-L564 | Your Guide to Requesting Employment Information

What Is Form CMS-L564?

Direct answer: Form CMS-L564, “Request for Employment Information,” is how you prove you had qualifying employer group health coverage when enrolling in Medicare during a Special Enrollment Period (SEP) — the path available if you or your spouse delayed Medicare because of active employer coverage. It must be submitted together with your actual Part B enrollment application, Form CMS-40B, not on its own. Getting this pairing and the documentation right the first time is what keeps your enrollment from stalling or triggering a late penalty you shouldn’t owe.

How Does Delayed Medicare Enrollment Actually Work?

When you first become eligible for Medicare, typically at 65, you have a seven-month Initial Enrollment Period (IEP) — the month you turn 65, plus three months before and three months after.

Missing that window generally pushes you into the General Enrollment Period (GEP), an annual fallback that can carry a late enrollment penalty. But if you or your spouse are still actively working and covered by a qualifying employer group health plan, you may be able to delay Medicare without penalty and use a Special Enrollment Period once that coverage ends instead.

How Does the Special Enrollment Period Work?

• Qualifying for the SEP generally requires creditable coverage through an employer with 20 or more employees (different, more specific rules can apply if you qualify for Medicare due to a disability).
• Timing: your SEP for Part A and/or Part B lasts eight months, starting the month after active employment ends or your group health coverage based on that employment ends — whichever happens first. Your prior coverage generally can’t have ended more than eight months before you apply.
• Proof required: you’ll need to document that coverage using Form CMS-L564.
• Penalty risk: missing your SEP window can mean a late enrollment penalty — roughly 10% added to your Part B premium for each full 12-month period you could have had Part B but didn’t.
• Employer size matters. SEP eligibility rules differ depending on your employer’s size, so confirm directly with your employer’s benefits administrator rather than assuming general rules apply to your specific situation.

Who Is Eligible to Use Form CMS-L564?

You need to meet several criteria together:

• You’re applying for Medicare and haven’t yet started receiving Social Security benefits.
• You (or your spouse, or a qualifying family member if you’re disabled) are actively employed.
• You’re enrolled in that employer’s active group health plan coverage.
• The employer generally has 20 or more employees.

How Do I Get Form CMS-L564?

You can download it directly from CMS’s website, request a copy by calling Social Security, or pick one up in person at your local Social Security office. Confirm you’re using the most current version of the form before filling it out, since using an outdated version can cause processing delays.

How Do I Fill Out Form CMS-L564?

The form has three sections:

Section A — Worker Information: your Social Security number, full legal name, birth date, phone number, and current address.

Section B — Employer Information: your employer’s legal name and address, confirmation of group health plan coverage, and the specific start and end dates of that coverage. Precision on the dates matters — your coverage needs to be verified as continuous from the first month you were eligible for Medicare Part B through when it ended, so incomplete or vague date ranges can cause real delays.

Section C — Employer Acknowledgment: a signature from an authorized company representative, the date signed, their title, and a contact phone number.

What Documentation Do I Need to Submit With the Form?

To avoid delays, include:

• Proof of employment — a letter on company letterhead verifying your employment dates, especially if you’ve recently retired.
• Proof of group health plan coverage — a statement or certificate confirming your enrollment dates under the employer’s plan.
• Proof of coverage end date, if applicable, showing exactly when your employer coverage terminated.

Make sure every document clearly shows your name and matches the dates on the form itself — mismatches between documents are a common, avoidable cause of processing delays.

How and Where Do I Submit Form CMS-L564?

This is a detail the process gets wrong often enough to call out clearly: Form CMS-L564 must be submitted together with Form CMS-40B, your actual Application for Enrollment in Medicare Part B — not on its own. Submitting the L564 alone without the 40B doesn’t complete your enrollment.

What If My Employer Won’t Complete Section B?

First, try to understand why — it’s often simply unfamiliarity with the form’s purpose, which can be resolved by explaining it’s required for your Medicare Part B enrollment waiver. If your employer remains unwilling to cooperate, contact the Social Security Administration directly for guidance on alternative documentation that may be accepted instead, such as W-2 forms, pay stubs, or health insurance cards showing your coverage.

What Common Mistakes Should I Avoid?

• Incomplete fields — missing information causes processing hold-ups.
• Inaccurate dates — double-check employment and coverage dates against your supporting documents before submitting.
• Submitting CMS-L564 without CMS-40B — remember, these need to go together.

If you discover an error after submission, contact the SSA to retrieve the form, correct the error in ink with your initials next to the change, and resubmit promptly.

Bottom Line

Form CMS-L564 exists to prove you had qualifying employer coverage so you can enroll in Medicare through a Special Enrollment Period without a late penalty — but it only works when submitted correctly, paired with your CMS-40B application, with accurate dates that match your supporting documentation. Getting this right the first time avoids the delays and resubmissions that can otherwise eat into your SEP window. Keep a copy of everything you submit, and don’t hesitate to follow up with your local Social Security office if you haven’t heard back within a reasonable time.

Key Takeaways

• Form CMS-L564 proves employer group health coverage for a Medicare Special Enrollment Period and must be submitted together with Form CMS-40B, your actual Part B enrollment application.
• Your Special Enrollment Period lasts eight months from when active employment or employer coverage ends, whichever comes first.
• Submission is by mail, fax, or in person to your local Social Security office — there’s no full online e-filing option currently available for this form pairing.
• Missing your SEP can result in a permanent late enrollment penalty added to your Part B premium.
• If your employer won’t complete Section B, alternative documentation like W-2s or pay stubs may be accepted with SSA guidance.
• Accurate, matching dates across the form and your supporting documents are essential to avoid processing delays.

FAQ – Medicare Form CMS-L564

What is Form CMS-L564 used for?
Proving you had qualifying employer group health coverage, so you can enroll in Medicare during a Special Enrollment Period without a late penalty.

Do I submit CMS-L564 by itself?
No. It must be submitted together with Form CMS-40B, your actual Medicare Part B enrollment application — submitting the L564 alone doesn’t complete your enrollment.

What if my employer refuses to fill out Section B?
Contact the Social Security Administration for guidance on alternative documentation, such as W-2 forms, pay stubs, or health insurance cards showing your coverage dates.

How long is my Special Enrollment Period?
Eight months, starting the month after your active employment or employer-based group health coverage ends, whichever happens first.

What happens if I miss my SEP?
You may need to wait for the next General Enrollment Period and could face a permanent late enrollment penalty added to your Part B premium.