If You Are Age 65 or Over
If you or your spouse works for an employer with at least 20 employees, and one of you becomes eligible for Medicare at age 65, the employer must offer you the same health coverage it offers other employees. This is known as a Group Health Plan (GHP). The employer’s GHP can, and often does, provide benefits Medicare doesn’t cover, such as dental care, vision coverage and hearing aids.
Employers with 20 or more employees must provide you with coverage that is primary and pays those health benefits first. An employer of this size cannot provide you with coverage that is secondary to Medicare or that supplements Medicare’s benefits.
Employers with fewer than 20 employees are not required to provide you with the same health coverage as other employees if you are eligible for Medicare. These small employers generally require you to enroll in Medicare to reduce the premium they pay for employee health benefits. A small employer may, however, offer you secondary or supplemental coverage that is or acts like a Medigap plan and costs less than primary coverage for someone age 65 or over.
If You Are Younger than Age 65
If you are eligible for Medicare because of a disability (except end-stage renal disease — ESRD) before you are age 65, and your spouse or a qualified family member works for an employer with 100 or more employees, the employer must offer you the same health coverage as other workers, their spouses and dependents. This is known as a Large Group Health Plan (LGHP). If you are covered by the employer’s health plan, it will be the primary insurer and Medicare will be secondary.
Employers with fewer than 100 employees are not required to provide you with the same health coverage as other employees, but they may provide you with secondary coverage.
If you are younger than age 65, on Medicare because of ESRD, and you are covered by an employer Group Health Plan (GHP), the plan is required to pay first for 30 months following the effective date of your Medicare benefits. This is called the Coordination of Benefits (COB) Period and applies regardless of the size of the group or whether you are working. If you have Medicare because of ESRD, many of the rules discussed in this section do not apply to you. See our fact sheet Medicare and People with End-Stage Renal Disease (ESRD) (PDF).
Note: Special rules may apply when domestic partners, other family members and dependent adult children with Medicare are covered by another person’s GHP. For more information, visit the Social Security Administration (SSA) website or call 1-800-772-1213.