Breast screening no longer starts late in Ontario. What women need to know from age 40

By Tahani Elghazaly
Published April 7, 2026

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Women in Ontario no longer have to wait until age 50 to start thinking seriously about organized breast screening. Since October 2024, Ontario’s breast screening program has expanded to include people aged 40 to 49, alongside the long-standing 50 to 74 age group. The shift matters because breast cancer remains the most commonly diagnosed cancer among women in Canada. In 2025, an estimated 31,900 women in Canada are expected to be diagnosed with breast cancer, representing 26 percent of all new cancer cases in women.

For most readers, the practical question is eligibility. In Ontario, people aged 40 to 74 at average risk may qualify for screening through the Ontario Breast Screening Program if they have no breast cancer symptoms, no personal history of breast cancer, have not had a mastectomy, and have not had a screening mammogram within the last 11 months. Official eligibility also includes women, Two-Spirit people, trans people and nonbinary people who meet the program criteria.

The other major change is access. Eligible people aged 40 to 74 can contact an Ontario Breast Screening Program location directly to book a mammogram, rather than relying in every case on a primary care referral. Ontario Health also provides an official wait-times tool that lets users search by location, language, accessibility needs and appointment availability.

For screening frequency, Ontario recommends mammography every two years for most eligible participants. For people aged 40 to 49, the province encourages an informed decision, meaning women should weigh the potential benefits and possible downsides of screening with a family doctor, nurse practitioner or a Health811 navigator if they do not have a regular provider.

One point should not be missed: organized screening is for people without symptoms. If a woman notices a lump, persistent redness, nipple changes or another concerning breast change, she should not wait for a routine screening appointment. She should seek medical assessment directly. Ontario also has a separate high-risk screening stream for eligible people aged 30 to 69, while people over 74 can continue screening after discussing it with a healthcare provider.

In practical terms, Ontario’s message is now much clearer than before: age 40 is no longer too early to start the conversation about breast screening. For many women, that means earlier access, simpler booking and fewer reasons to delay.