When Is Medicare Your Primary Insurance? 

Once you become eligible for Medicare, it’s not uncommon to have other health coverage in addition to Medicare Parts A and B. These might include coverage through an employer, Medicaid, or retiree health plans. 

Understanding how Medicare coordinates with other insurance is key to making sure your medical bills are paid correctly. Knowing whether Medicare is your primary or secondary insurance can help prevent delays or unexpected out-of-pocket costs. 

What Is Primary vs. Secondary Insurance? 

If you have more than one type of health coverage, one plan will be designated as the primary payer—this is the plan that pays first when you receive care. Any additional plan you have will be considered secondary, meaning it may cover costs not fully paid for by the primary insurance. After both plans pay their share, any remaining costs are typically your responsibility. 

The order in which your insurance plans pay is determined by a set of rules created to coordinate benefits. Understanding these rules is especially important when you’re new to Medicare or managing multiple forms of coverage. 

Situations Where Medicare Is Primary 

In many cases, Medicare automatically becomes your main form of insurance once you're eligible for Parts A and B. Here are common scenarios where Medicare pays first: 

• Medicare is your only coverage: If you’re not covered by any other health insurance, then Medicare Parts A and B (or a Medicare Advantage plan, if you’ve chosen that route) will be your primary source of coverage. 

• You have a Medigap plan: If you’ve purchased a Medicare Supplement Insurance (Medigap) policy, Medicare remains the primary payer, and the Medigap policy helps cover costs that Medicare doesn’t fully pay. 

• You have a small employer group plan (fewer than 20 employees): Medicare pays first if you’re still working and covered by a health plan through a smaller employer. 

• You are enrolled in Medicaid: If you qualify for both Medicare and Medicaid (known as "dual eligibility"), Medicare pays first, and Medicaid may help cover remaining costs. 

• You have retiree insurance: If your former employer provides retiree health coverage, Medicare becomes the primary payer once you turn 65. 

• You are covered by COBRA: If you enroll in COBRA after becoming eligible for Medicare, Medicare is the primary payer, and COBRA coverage is secondary. 

When Medicare Is Secondary 

There are fewer situations where Medicare pays second: 

• You have a group plan from a large employer (20 or more employees): If you’re still working and your employer provides coverage for 20 or more employees, that group plan pays first, and Medicare is secondary. 

• You are receiving workers’ compensation: If your healthcare services are related to a workers’ compensation claim, that coverage pays first. For services unrelated to the claim, Medicare remains primary. 

How to Be Sure 

If you're ever unsure which insurance is considered primary, review your plan documents or contact your insurance providers directly. It’s also helpful to inform Medicare about any other health coverage you have to ensure that claims are processed correctly and in the right order. 

If you have questions or need assistance finding a health plan, call one
of our Licensed Agents at
Trusted Senior Specialists. There is no cost or obligation for a consultation! 

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