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How do I apply for Medicare if I delayed past 65?

Applying late has an extra step most people miss: the employment verification forms that keep you out of a penalty.

Updated August 17, 2026 · 3 min read

Enrolling after 65 is normal and often correct. Plenty of people work past 65 with good employer coverage and delay Part B on purpose. The application just has an extra step, and skipping it is what triggers a penalty you did not earn.

The two forms that matter

If you delayed because of employer coverage, you do not use the standard online application alone. You file two forms together.

• CMS-40B, the application for enrollment in Part B
• CMS-L564, request for employment information, which your employer completes

The L564 is the important one. It is your employer certifying that you had group health coverage based on active employment, which is the proof that you qualify for a Special Enrollment Period rather than a late penalty.

If your employer no longer exists

This happens and it is not fatal. Social Security will accept alternative proof of coverage.

• Pay stubs showing health insurance premium deductions
• W-2 forms showing employer contributions to health coverage
• Health insurance cards with effective dates
• Explanation of benefits statements from the group plan
• Written statements from the insurance carrier confirming coverage dates

Gather what you can and bring it in person rather than mailing it. An in office visit resolves these situations far faster.

Your window and how long it lasts

Eight months from the end of employment or the end of the group coverage, whichever comes first, to enroll in Part B without penalty.

Part D is only two months. That mismatch is why people clear the Part B deadline and still get a drug penalty. Handle both in the same sitting.

When your coverage starts

You can request that Part B begin the month you file, or up to three months later. Coordinate that start date with the end of your employer coverage so you do not create a gap, and do not double pay for a month you did not need.

The order to do this in

1. Ask HR for the CMS-L564 as soon as you know your retirement date, before your last day while you still have easy access to them.
2. Complete CMS-40B yourself.
3. Submit both to Social Security, ideally in person, and keep copies of everything.
4. Once your Medicare number arrives, choose a Part D plan or an Advantage plan immediately. The two month clock is already running.
5. If you are going the supplement route, note that your Medigap open enrollment runs six months from when Part B starts, and that protection does not come back.

That last point deserves attention. Delaying Part B also delays your one guaranteed shot at buying a Medicare Supplement with no health questions. Read how the windows interact.

One thing to check first

If you contributed to a Health Savings Account while working, stop contributions at least six months before you file. Part A can be backdated up to six months, and contributions made during those months become excess and get taxed. See the HSA trap.