How does Medicare work with employer insurance?

If you have insurance through your employer or spouse’s employer when you become eligible for Medicare, you can delay Medicare enrollment without penalty.

You also have the option of enrolling in Medicare while still receiving company provided insurance. Medicare can work with employer provided insurance, but does so differently based on the size of the employer. If the employer provided insurance comes from a company with fewer than 20 employees, then Medicare pays primary, and you may be required to activate Part B at the same time your Part A goes into effect. To find out if you need to activate your Part B benefits, contact your employer’s benefits manager. If your employer provided insurance comes from a company with more than 20 employees, Medicare pays secondary.

Once you stop working or lose your employer coverage, you have an eight month window to enroll in Part B without penalty.