Short answer: Medicare Part B usually covers services in a hospital emergency department for an injury, sudden illness, or illness that quickly becomes worse. Emergency department care is outpatient care unless a doctor formally admits the patient as an inpatient.
Original Medicare coverage
Part B covers the emergency department visit, doctor services, diagnostic tests, imaging, and other medically necessary outpatient hospital services under their applicable rules. A person may remain in the hospital overnight and still be an outpatient if no formal inpatient admission order has been made.
If the patient is admitted to the same hospital for a related condition within three days, Medicare generally treats the related emergency services as part of the inpatient stay. Part A then applies to the inpatient hospital services, while doctor services remain covered under Part B.
Eligibility and limits
Coverage applies to medically necessary emergency evaluation and treatment. Medicare covers emergency services outside the United States only in limited situations. Ambulance transportation has separate medical-necessity and destination rules. Prescription drugs that a patient normally takes independently may not be covered by Part B in an outpatient hospital setting.
Costs
You may pay a copayment for the emergency department visit and for individual hospital services. After the Part B deductible, you generally pay 20 percent of the Medicare-approved amount for doctor services. If the visit becomes part of a qualifying inpatient admission, the outpatient copayments may not apply as separate charges.
Medicare Advantage
Medicare Advantage plans cover emergency services. Emergency care is covered without the ordinary requirement to use an in-network hospital, although plan cost sharing and follow-up rules apply. Notify the plan after emergency care when the plan requests it.
What to do next
- Call 911 or seek emergency care when needed.
- Ask the hospital whether you are an inpatient or an outpatient under observation.
- Keep coverage notices and discharge documents.
- Contact the plan about follow-up care after the emergency is controlled.
Coverage is determined from the claim, the patient’s eligibility, provider status, and applicable Medicare rules. A provider’s recommendation does not guarantee payment. Before a planned service, ask the provider what will be billed and ask Medicare or the plan whether any coverage review is required.
Sources
Last reviewed: August 2026. Medicare rules and plan benefits can change.