Regular mammograms remain one of the most effective ways to catch breast cancer early, when treatment options are broadest. If you are on Medicare, the annual screening mammogram is one of the program's most straightforward benefits — covered with no cost-sharing, year after year, with no upper age limit. But the moment a radiologist wants a closer look, the billing rules change. Understanding the line between a screening mammogram and a diagnostic one can save you from an unexpected bill. Here is how Medicare handles both in 2026, plus what the rules say about 3D imaging and dense breast tissue.
The Short Answer
Medicare Part B covers a screening mammogram every 12 months at $0 — no Part B deductible and no coinsurance — for women age 40 and older, with no upper age limit. Medicare also covers one baseline mammogram for women ages 35 to 39.
A few points that make this benefit unusually simple:
- No referral is needed. You can schedule your screening mammogram directly, and this applies even in Medicare Advantage plans when you use an in-network facility.
- 3D mammography (digital breast tomosynthesis) is included. When performed as part of your screening, 3D imaging is covered at the same $0 cost-sharing as a standard 2D mammogram.
The screening mammogram sits alongside a long list of preventive benefits Medicare covers with no cost-sharing — our guide to Medicare preventive services and screenings covers the full lineup. Your annual wellness visit is also a natural time to make sure you are up to date on this and other screenings.
Screening vs. Diagnostic: Where the Bill Changes
A diagnostic mammogram is one your doctor orders to investigate something specific — a lump, pain, nipple discharge, or a suspicious finding on a screening image. Medicare covers diagnostic mammograms as often as medically necessary, including more than once a year. But the cost-sharing is different:
- You first meet the Part B annual deductible of $283 (2026), if you have not already
- Then you pay 20% coinsurance of the Medicare-approved amount
The same visit can feel identical from the exam table, which is why it helps to know how the order was written before you arrive. If the difference between coinsurance and flat copayments is fuzzy, see our guide to copays vs. coinsurance. For a broader look at how Medicare handles imaging and testing generally, see Medicare lab tests and diagnostic services.
Two situations worth flagging:
- After breast cancer treatment, follow-up mammograms are generally billed as diagnostic for roughly 3 to 5 years, even if you feel fine — meaning the deductible and 20% coinsurance apply during that surveillance period. Our guide to Medicare and cancer treatment covers what else to expect during and after treatment.
- Men can receive Medicare-covered diagnostic mammograms when medically necessary, but there is no screening mammogram benefit for men.
What About Dense Breasts?
Since September 2024, FDA rules have required mammography facilities to notify every patient whether they have dense breast tissue — and about half of women do. Dense tissue can make cancers harder to spot on a mammogram, so many women who receive that notice ask whether Medicare will pay for a supplemental ultrasound or breast MRI.
Here is the honest answer: breast density alone does not qualify for Medicare-covered supplemental imaging. Medicare covers a breast ultrasound or MRI only when there is a diagnostic reason — a suspicious finding on the mammogram, a palpable mass, or an inconclusive workup that needs more imaging. When one of those applies, the supplemental imaging is billed as diagnostic: 20% coinsurance after the $283 deductible (2026).
If you receive a density notice, talk with your doctor about your overall risk. If your doctor identifies a clinical concern, the follow-up imaging may be covered; if the only finding is density itself, you would generally pay for supplemental screening out of pocket.
How Medicare Advantage Handles Mammograms
Medicare Advantage plans must cover everything Original Medicare covers, including the $0 annual screening mammogram — and, notably, no referral is required for the screening even in plans that normally use referrals, as long as you stay in-network. Plan-specific rules to keep in mind:
- Network rules — using an in-network imaging facility is generally required for the $0 screening benefit
- Diagnostic mammogram cost-sharing varies by plan, often as a flat copay rather than 20% coinsurance
- Every Medicare Advantage plan includes an annual maximum out-of-pocket limit on covered services — see our guide to Medicare out-of-pocket limits
For more on how these plans are structured, see our overview of Medicare Advantage (Part C).
Questions to Ask Before Your Appointment
A quick check with your doctor's office or the imaging center can prevent surprises:
- Is this visit being billed as a screening or a diagnostic mammogram?
- Has it been 12 months since my last screening mammogram? Scheduling a few days early can cause a claim denial.
- If I need additional views or an ultrasound the same day, how will those be billed?
- Does the facility accept Medicare assignment? The $0 screening benefit depends on it.
How to Get Help and Learn More
If you want to confirm coverage details or talk through your options, these official resources can help:
- Medicare.gov — See the official coverage page at medicare.gov/coverage/mammograms.
- 1-800-MEDICARE (1-800-633-4227) — Medicare's official helpline can answer coverage and billing questions. TTY users can call 1-877-486-2048.
- State Health Insurance Assistance Program (SHIP) — SHIP offers free, unbiased counseling on what you would pay under your specific coverage. Find your local program at shiphelp.org or by calling 1-800-MEDICARE.
Summary and Next Steps
Medicare's mammogram benefit is simple on the screening side and more nuanced once a workup begins. Key points to remember:
- Screening mammograms are covered at $0 every 12 months for women 40 and older, with no upper age limit and no referral needed
- One baseline mammogram is covered for women ages 35 to 39
- 3D mammography is included in the screening benefit at no cost-sharing
- Diagnostic mammograms are covered as often as medically necessary, at 20% coinsurance after the $283 deductible (2026)
- After breast cancer treatment, mammograms are generally billed as diagnostic for about 3 to 5 years
- Breast density alone does not trigger covered supplemental imaging — an ultrasound or MRI generally requires a diagnostic reason
- Medicare Advantage plans cover the $0 screening in-network, with plan-specific rules for diagnostic imaging
If it has been more than a year since your last mammogram, scheduling one is a simple next step — no referral, no bill, no deductible. And if you ever receive a bill for what you believed was a screening, your local SHIP counselor can help you sort it out for free.
