Starting at age 40, most women should get a mammogram every two years at minimum. That’s the baseline recommendation from the U.S. Preventive Services Task Force, which updated its guidelines in 2024 to lower the starting age from 50 to 40. But depending on which medical organization you ask, the recommended frequency ranges from every year to every two years, and your personal risk factors can shift that schedule significantly.
What the Major Guidelines Recommend
The three organizations women hear about most each take a slightly different position, which is why this question gets confusing fast.
The U.S. Preventive Services Task Force (USPSTF) recommends a mammogram every two years from age 40 through 74. This is the guideline that drives insurance coverage, and it reflects modeling data showing that biennial screening starting at 40 averts about 8.2 breast cancer deaths per 1,000 women screened over a lifetime, compared to 6.7 deaths averted when screening starts at 50.
The American Cancer Society takes a more age-specific approach. Women 40 to 44 have the option to start yearly screening. Women 45 to 54 should get mammograms every year. At 55 and older, women can switch to every other year or continue annually. Screening should continue as long as you’re in good health and expected to live at least 10 more years.
The American College of Radiology recommends annual mammograms starting at 40 for all women at average risk. Their position is the most aggressive: they cite data showing annual screening from ages 40 to 84 reduces breast cancer mortality by 40%, compared to a 23% reduction with biennial screening from 50 to 74. In absolute numbers, that’s roughly 12 lives saved per 1,000 women screened annually versus 7 per 1,000 screened every two years.
Annual vs. Every Two Years
The gap between “every year” and “every two years” isn’t just a scheduling preference. It reflects a genuine trade-off between catching more cancers early and exposing more women to false alarms.
More than half of women screened annually for 10 years will get at least one false-positive result, meaning the mammogram flags something that turns out not to be cancer. Many of those women will undergo a biopsy as part of follow-up testing. False positives are more common in your 40s because breast tissue tends to be denser before menopause, making images harder to read. Younger women, women with dense breasts, women with prior biopsies, and those with a family history of breast cancer are all more likely to experience a false positive.
That said, breast cancers in younger women can grow faster between screenings. Annual mammograms catch more of these interval cancers. The ACR’s modeling shows annual screening from age 40 achieves a 40% mortality reduction, while biennial screening from the same age achieves 32%. Whether that 8-percentage-point difference justifies the additional false positives and callbacks is something you’ll weigh based on your own comfort level and risk profile.
When You Should Start Earlier or Screen More Often
The guidelines above apply to women at average risk. If you fall into a higher-risk category, screening typically starts earlier and includes additional imaging beyond standard mammography.
You’re considered high risk if you carry a BRCA1 or BRCA2 genetic mutation (or certain other inherited mutations), have a first-degree relative with breast cancer even without confirmed genetic testing, received chest radiation before age 30, have a personal history of breast cancer or high-risk breast lesions, or have a calculated lifetime risk of 20% or more. Women with very dense breast tissue also face elevated risk.
For high-risk women, the ACR recommends annual screening mammograms starting at age 30, not 40. Women with a history of chest radiation before 30 should start at 25 or eight years after radiation, whichever comes later. High-risk women are also recommended to get an annual breast MRI in addition to their mammogram, starting as early as 25 to 30.
If You Have Dense Breasts
Breast density matters for two reasons: dense tissue raises your cancer risk, and it also makes mammograms harder to interpret because both dense tissue and tumors appear white on the image. Most states now require that mammography facilities notify you if you have dense breasts.
Breast density is graded on a four-level scale, from mostly fatty to extremely dense. If your breasts fall into the two denser categories (heterogeneously dense or extremely dense), supplemental screening beyond a standard mammogram may help. For women with extremely dense breasts and average risk, breast MRI is generally considered the most effective supplemental tool, with a higher detection rate than ultrasound. Ultrasound is a reasonable alternative if MRI isn’t accessible or feasible. For women with heterogeneously dense breasts, MRI or ultrasound may be appropriate depending on your overall risk picture.
What Screening Means for Black Women
Black women develop breast cancer at younger ages on average and are more likely to be diagnosed with aggressive subtypes. The USPSTF modeling data reflects this: biennial screening starting at 40 averts 10.7 breast cancer deaths per 1,000 Black women screened, compared to 9.2 when starting at 50. That 1.8 additional deaths averted per 1,000 women is a larger absolute benefit than the 1.3 seen in the general population. Starting at 40 rather than waiting until 50 is particularly important for Black women.
Insurance Coverage After 40
Under the Affordable Care Act, all Marketplace health plans and many other insurance plans must cover screening mammograms for women 40 and older every one to two years with no copay, coinsurance, or deductible. This applies whether you choose annual or biennial screening. If you’re on a plan that follows ACA preventive care rules, cost should not be a barrier to getting screened on whatever schedule you and your doctor choose.
Preparing for Your Mammogram
On the day of your exam, skip deodorant, antiperspirant, powders, lotions, creams, and perfumes on or near your breasts and underarms. These products can contain particles that show up as white spots on the image, potentially mimicking or obscuring findings. You can bring deodorant to apply afterward. If your breasts tend to be tender, scheduling the mammogram for a week or two after your period, when breast tissue is least sensitive, can make the compression more comfortable.