20+Employees: employer plan usually pays first
Under 20Employees: Medicare usually pays first
AlwaysMedicare first for COBRA and retiree plans
LastMedicaid pays after other coverage
Who pays first
| Your situation | Pays first | Pays second |
|---|---|---|
| Group plan from your or your spouse's current job, employer has 20 or more employees | Employer plan | Medicare |
| Group plan from current job, employer has fewer than 20 employees | Medicare | Employer plan |
| COBRA continuation coverage | Medicare | COBRA |
| Retiree coverage from a former employer | Medicare | Retiree plan |
| Under 65 with disability, group plan from current job at an employer with 100 or more employees | Employer plan | Medicare |
| Under 65 with disability, smaller employer | Medicare | Employer plan |
| End-stage renal disease (kidney failure), group health plan | Group plan for the first 30 months of Medicare eligibility | Medicare |
| End-stage renal disease, after 30 months | Medicare | Group plan |
| Medicaid | Medicare and other insurance | Medicaid pays last |
| TRICARE for Life | Medicare | TRICARE for Life |
These are general rules. Special rules apply to some multi-employer plans and to federal employee coverage.
Why it matters
- Part B timing: if Medicare is your primary payer, such as when you work for a small company, skipping Part B can leave you with large unpaid bills. See the Special Enrollment Period guide.
- Claims: your provider should bill the primary payer first. If they bill the wrong one, the claim may be denied.
- Out-of-pocket costs: a secondary plan may pay only what the primary plan did not and what it would have paid on its own.
Accidents, workers' comp and liability
If your injury is covered by workers' compensation, no-fault insurance, or a liability claim, those typically pay first for related care. Medicare may make a conditional payment and later be reimbursed.
What to do
- Ask your employer's benefits office how many employees the company has and whether your plan is primary or secondary to Medicare.
- Give providers both insurance cards and tell them which is primary.
- Report any change (retiring, leaving a job, a spouse starting or stopping work) to Medicare at 1-800-MEDICARE.
COBRA is not a shield. If you are 65 or older and rely on COBRA instead of Medicare Part B, Medicare is the primary payer and the COBRA plan may refuse to pay as it would have. Enroll in Part B on time.
Having both Medicare and Medicaid? Medicare pays first. See Medicare vs Medicaid.