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What is Form CMS-L564 and what is it used for?

What is Form CMS-L564 and what is it used for?

Enrollment
Last updated: 
April 10, 2026
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The short answer

Form CMS-L564 is a form your employer completes to confirm you had employer-sponsored group health coverage. You use it when enrolling in Medicare Part B outside your Initial Enrollment Period to avoid a late penalty.

The full explanation

When most people turn 65, they have a limited window to sign up for Medicare Part B, the part that covers doctor visits and outpatient care. If you miss that window, you can face a permanent late enrollment penalty added to your premium.However, there is an exception. If you delayed Part B because you were covered by a group health plan through your own active employment or a spouse's active employment, you are entitled to a Special Enrollment Period. This lets you sign up for Part B without a penalty after that coverage ends.To use that Special Enrollment Period, Social Security needs proof that your delay was for a legitimate reason. That's where Form CMS-L564 comes in. Your employer fills out this form to confirm that you had employer-sponsored group health coverage and for what period. You submit it along with your Part B enrollment application, typically Form CMS-40B.A few things worth knowing: the coverage must be based on current, active employment, not retiree coverage or COBRA. Retiree insurance and COBRA do not qualify you for this exception. If your employer no longer exists or is unable to complete the form, there are alternate ways to document your coverage, but you should contact Social Security directly to work through that.

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In 

Utah

 specifically

Utah plan choices vary a lot by county. The Wasatch Front usually has more competition, while rural counties often have fewer Medicare Advantage options.

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What this means for you

For you, this means if you are still working at 65 and plan to delay Medicare Part B, keep records of your employer coverage so the enrollment process goes smoothly when you are ready to sign up.

Related Questions

How do I enroll in Part B after leaving employer coverage?

How long is my Special Enrollment Period after losing employer coverage?

How do I enroll in Medicare?

What documents do I need to enroll in Medicare?

Still have questions about Medicare?

Book a review with a licensed Medicare advisor.

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Medicare Advantage Plans in 

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Decision area Tool What it answers
Enrollment Initial Enrollment Period Calculator When your 7-month Medicare eligibility window begins and ends based on your 65th birthday
Enrollment When Should I Sign Up for Medicare? The best time to enroll based on your work status, other coverage, and age
Enrollment Special Enrollment Period Checker Whether a life event qualifies you for enrollment outside the standard windows
Enrollment Late Enrollment Penalty Checker How much extra you'll pay monthly if you missed your enrollment window
Enrollment Part B Penalty Calculator The exact 10%-per-year premium increase for delayed Part B enrollment
Enrollment Part D Penalty Calculator The 1%-per-month premium increase for gaps in creditable drug coverage
Costs Cost Scenario Planner Estimated annual spending across plan types at different health utilization levels
Costs Advantage vs. Medigap Cost Comparison True cost difference between Medicare Advantage and Original Medicare with Medigap
Costs IRMAA Calculator Whether your income triggers higher Part B and Part D premiums
Costs Part A Premium Estimator Your monthly Part A premium based on work history and quarters of coverage
Costs M3P Calculator How the Medicare Prescription Payment Plan smooths your drug costs into monthly payments
Coverage Doctor & Drug Assessment Whether your providers and prescriptions are covered by a specific plan
Coverage Part D Shopping Tool Which Part D plan has the lowest total annual cost for your specific medications
Coverage Travel & Network Risk Assessment How your coverage works outside your home area and which plan types travel best
Employer/COBRA COBRA vs. Medicare Why COBRA can trigger permanent Medicare penalties and how costs compare
Employer/COBRA Employer Coverage vs. Medicare Whether your employer plan or Medicare is primary and when to transition
Employer/COBRA HSA & Medicare Compatibility How Medicare enrollment affects HSA eligibility and what to do before enrolling
Planning Caregiver Readiness Checklist Whether you have everything in place to help a loved one with Medicare decisions
Planning Document Gatherer Which documents you need to have ready before enrolling or changing plans
Planning Medigap Fit Assessment Whether Medigap or Medicare Advantage is the better fit for how you use healthcare
Planning Medigap Open Enrollment Window Whether you're inside your one-time guaranteed issue window for Medigap
Planning Medicare Savings Program Eligibility Whether your income qualifies you for help paying Medicare premiums and cost-sharing

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‍Data & Methodology for Research Articles: All provider, facility, quality star ratings, and enrollment data is sourced from primary CMS records (cms.gov), including the December 2025 CPSC Enrollment files and the January 2026 Provider Data Catalog. Calculations for patient-to-provider ratios are performed using indexed clinician and facility data. Everything on restingsycamore.com is for educational purposes and does not constitute an endorsement of any specific plan or provider.

Non-CMS Data Sources: Some  specific data was obtained from https://opendata.gov