Enrolling in Medicare After Losing Employer Coverage

If you're losing employer health coverage, whether through retirement, a layoff, or a spouse's job change, you can enroll in Medicare through a Special Enrollment Period (SEP) without waiting for a general enrollment window and, in most cases, without a late enrollment penalty. This SEP applies if you or your spouse were still working and covered by an employer group health plan after you turned 65, since that coverage let you delay Medicare Part B without a penalty. Once that coverage ends, a clock starts, and understanding the timing is the most important part of getting this right.

When your Special Enrollment Period starts

The 8-month SEP begins the month after your employment ends or the month after your group health coverage ends, whichever happens first. It does not matter if you choose COBRA continuation coverage instead of Medicare; the SEP clock still starts when your active employer coverage stops, not when COBRA runs out. This is one of the most common mix-ups people run into, so it's worth confirming your exact coverage end date with your former employer's benefits office.

This SEP is separate from the standard Medicare enrollment periods that apply to most new enrollees, and it's also distinct from the events covered in a Medicare Special Enrollment Period for other qualifying events, like moving out of a plan's service area.

What you'll need to enroll

To enroll in Part B during this SEP, you'll typically submit two documents to the Social Security Administration (SSA):

• Form CMS-L564 (Request for Employment Information), partly completed by your employer to confirm your coverage dates
• Form CMS-40B (Application for Enrollment in Part B), if you only have Part A so far

You can find both forms and current submission instructions on Medicare.gov's Special Enrollment Period page and through the SSA. If your former employer is slow to complete their portion, SSA can sometimes accept other proof of coverage, such as pay stubs or benefit statements, so don't let a delayed form stop you from starting the process.

Don't forget Part D and Medigap timing

Losing employer coverage also opens a separate SEP for Medicare Part D (prescription drug coverage), so review your drug needs at the same time you handle Part B. If your former employer coverage included good drug benefits, ask them for a notice of creditable coverage, since this documentation can matter later.

You'll also want to consider a Medigap (Medicare Supplement) policy. In most states, losing employer coverage and enrolling in Part B for the first time triggers a Medigap open enrollment window with guaranteed issue rights, meaning insurers can't deny you a policy or charge more based on health conditions during that window. This window is time-limited, so it's worth comparing options before it closes rather than after.

Who this SEP applies to

This SEP is specifically for people who delayed Medicare because they had coverage through their own or a spouse's current employment at a company with 20 or more employees (or, in some cases, smaller employers with different rules). It does not apply to retiree coverage, COBRA, or individual marketplace plans, those don't count as active employer coverage for SEP purposes. If you're unsure whether your prior plan qualifies, reviewing the basics of Medicare eligibility and how it interacts with employer plans can help clarify your situation before you file.