Medicare covers most surgeries, but not all of them, and the amount you pay depends on which part of Medicare you have and where the surgery happens

If you have Original Medicare (Part A and Part B), surgery in a hospital or outpatient surgical center is covered. Part A covers the facility, the operating room, and your hospital stay if needed. Part B covers the surgeon's fee and the anesthesiologist. If you have a Medicare Advantage plan (Part C), your coverage works differently — your plan decides what surgeries it covers and how much you pay, though it must cover at least what Original Medicare does.

The catch is that Medicare only covers surgeries it considers medically necessary. A surgery is medically necessary when a doctor documents that it treats a condition, relieves pain, or restores function — not when it is cosmetic or elective. Medicare will not cover a facelift, most dental work, or vision correction surgery. It also will not cover experimental procedures unless you are in a clinical trial that Medicare has approved.

Key Takeaways

  • Original Medicare Part A covers the hospital or surgical facility; Part B covers the surgeon and anesthesiologist for medically necessary procedures.
  • Medicare Advantage plans must cover what Original Medicare covers, but may have different copays, deductibles, or require you to use in-network surgeons.
  • You will owe a Part B deductible before coverage starts, then coinsurance (usually 20% of the surgeon's fee) after that.
  • Outpatient surgery in a doctor's office or ambulatory surgical center may have lower out-of-pocket costs than hospital surgery.
  • Your doctor must document medical necessity, and Medicare may deny the surgery if it determines the procedure is not medically necessary for your condition.

What you pay for surgery under Original Medicare

Under Original Medicare, you pay the Part B deductible first — this is a set amount each year (it changes annually). After you meet the deductible, you pay coinsurance, which is usually 20% of what Medicare approves for the surgeon's fee and anesthesia. You do not pay coinsurance for the hospital facility itself under Part A, but you do pay a hospital deductible if you are admitted as an inpatient.

The amount Medicare approves is not always what the surgeon charges. Medicare sets a fee schedule for each procedure in each region. If your surgeon accepts Medicare assignment, they agree to accept Medicare's approved amount as full payment (except for your coinsurance). If they do not accept assignment, they can charge up to 15% more than the approved amount, and you owe that difference on top of your coinsurance.

If your surgery requires an overnight hospital stay, Part A covers the room, meals, nursing care, and basic supplies. You pay a deductible for the first day, then nothing for days 2 through 60. Days 61 and beyond cost you a daily coinsurance amount. Most surgeries do not require a long stay, so your Part A costs are often just the deductible.

How Medicare Advantage plans handle surgery costs

With a Medicare Advantage plan, your out-of-pocket costs depend on your specific plan. Most plans have a copay for surgery — you might pay $250 to $500 per procedure — rather than a percentage coinsurance. Some plans have no copay for in-network surgeries but charge more if you use an out-of-network surgeon.

The important difference is that Medicare Advantage plans can require you to get approval before surgery. This is called prior authorization. Your doctor's office usually handles this, but the plan can deny the request if it does not agree the surgery is medically necessary. If the plan denies it and you have the surgery anyway, you may owe the full cost.

Medicare Advantage plans must cover emergency surgery without prior authorization, even if the surgeon is out of network. If you need urgent surgery and cannot reach your plan first, have the surgeon contact the plan when ready after the procedure to explain the emergency.

Outpatient surgery versus inpatient surgery

Outpatient surgery means you go home the same day. Inpatient surgery means you stay overnight or longer. For the same procedure, outpatient surgery usually costs you less because you do not owe a hospital inpatient deductible — you only owe Part B coinsurance for the surgeon and anesthesiologist.

Medicare and your surgeon decide whether a procedure can be done outpatient based on the type of surgery and your health. Cataract removal, many joint injections, and some hernia repairs are commonly done outpatient. Major surgeries like joint replacement or cardiac surgery usually require a hospital stay.

If your surgery is scheduled at an ambulatory surgical center (a facility that is not a hospital), your costs are the same as outpatient hospital surgery — you owe Part B coinsurance but not a hospital deductible. Ask your surgeon where the procedure will happen and whether it will be outpatient or inpatient before the surgery date so you can estimate your costs.

When Medicare says no to a surgery

Medicare denies surgery coverage when it determines the procedure is not medically necessary for your condition. This happens most often with back surgery, joint surgery, and some cardiac procedures. Medicare has specific rules about which patients may have access to for each surgery — for example, Medicare may cover back surgery only after you have tried physical therapy for a certain number of weeks.

If Medicare denies your surgery, your doctor can appeal the decision. The appeal process takes time — usually several weeks — so talk to your doctor as soon as you get a denial letter. Your doctor can submit additional medical records or a letter explaining why the surgery is necessary for your specific case. If the appeal is denied, you can request an independent review by someone outside Medicare.

If you disagree with a denial and want to move forward with surgery anyway, you can pay out of pocket. Before you do, ask your doctor to explain Medicare's reason for the denial and whether the surgery is likely to help your condition. A denial does not mean the surgery will not work — it means Medicare does not cover it for your diagnosis.

Experimental and clinical trial surgeries

Medicare does not cover experimental surgeries outside of clinical trials. If your doctor recommends a new surgical technique or a procedure that is not yet standard treatment, ask whether it is part of a clinical trial. If it is, Medicare may cover it if the trial is approved by Medicare and meets certain standards.

To find out whether a trial is Medicare-approved, ask your doctor or call Medicare at 1-800-MEDICARE. You can also search ClinicalTrials.gov to see whether a trial near you is listed as Medicare-approved. If you enroll in an approved trial, Medicare covers the surgery and related care as part of the trial, though you may still owe your usual copays or coinsurance.

What to ask your doctor before surgery

Before you schedule surgery, ask your doctor these questions so you understand what Medicare will cover:

  • Is this surgery medically necessary, or is it elective or cosmetic?
  • Will the surgery be done in a hospital or an outpatient surgical center?
  • Will I need to stay overnight?
  • Does my surgeon accept Medicare assignment?
  • If I have a Medicare Advantage plan, does the plan require prior authorization, and will the surgeon handle that?
  • What is the estimated cost to me after Medicare pays?

If your doctor is unsure whether Medicare will cover the surgery, ask them to contact Medicare or your plan before the surgery date. This prevents surprises after the procedure.

Frequently Asked Questions

Does Medicare cover all surgeries?

No. Medicare covers surgeries that are medically necessary — meaning they treat a condition, relieve pain, or restore function. It does not cover cosmetic surgery, most dental procedures, or experimental surgeries outside of approved clinical trials. Your doctor must document medical necessity, and Medicare may deny coverage if it determines the surgery is not medically necessary for your specific condition.

What if my surgeon does not accept Medicare?

If your surgeon does not accept Medicare assignment, they can charge up to 15% more than Medicare's approved amount. You owe that extra amount on top of your normal coinsurance. Before surgery, ask your surgeon whether they accept Medicare assignment and what your total out-of-pocket cost will be.

Will I owe anything if I have a Medigap plan?

It depends on your Medigap plan. Some Medigap plans cover your Part B coinsurance, which means you owe little or nothing for surgery. Other plans cover only part of it. Check your Medigap plan documents or call the plan to find out what it covers for surgery.

Can Medicare Advantage deny surgery I need?

Yes, if the plan's prior authorization process determines the surgery is not medically necessary according to the plan's rules. However, the plan must cover what Original Medicare covers. If you disagree with the denial, you can appeal within the plan or request an independent review. Emergency surgery is covered even without prior authorization.

How long does it take Medicare to pay for surgery?

Medicare typically pays the surgeon and facility within two to four weeks after the surgery. You may receive a bill from the surgeon or facility before Medicare pays, but they cannot ask you to pay your coinsurance until Medicare has processed the claim and determined what it will pay.