Turning 40 brings a new question for many people in Ontario: should I start getting mammograms? On October 8, 2024, Ontario lowered the starting age for breast cancer screening to 40. If you are in your forties, you can now book a mammogram directly through the Ontario Breast Screening Program (OBSP), but that does not mean everyone must. Ontario Health (Cancer Care Ontario) describes this as an informed choice, and this guide helps you make it. If you are thinking about a mammogram in your 40s in Toronto, this guide also shows you how to book at Annex Medical Imaging.

Quick Summary

  • People ages 40 to 49 can self-refer to any OBSP location. You do not need a referral or an order from your doctor.
  • Most people in this age group who decide to be screened should be screened with mammography every 2 years.
  • Ontario Health encourages you to talk about your personal risk, and the potential benefits and potential harms of screening, with your health care provider or a Health811 navigator.
  • Booking line: 1-800-668-9304.

What Changed for People in Their 40s?

Since October 8, 2024, eligible people ages 40 to 49 can self-refer to any of the more than 240 OBSP locations across Ontario. The program is publicly funded and serves women, Two-Spirit people, trans people and nonbinary people. The full information is on the Ontario Health page Breast Cancer Screening for People Ages 40 to 49: What You Need to Know.

Can I Self-Refer? The Criteria

To book without a referral in your forties, Ontario Health lists these criteria:

  • you have no breast cancer symptoms;
  • you have no personal history of breast cancer; and
  • you have not had a screening mammogram within the last 11 months.

The OBSP also does not screen people who have had a mastectomy through the average-risk pathway, and transfeminine people should have used feminizing hormones for at least 5 years in a row. If you are unsure whether you meet the criteria, call the booking line or your health care provider.

Why the Decision Is Personal at This Age

Screening is not one-size-fits-all in your forties. Mammography can find breast cancer early, when treatment has a better chance of working. But like any medical test, it also has potential harms, and the balance between benefits and harms is different at different ages and for different people. That is why Ontario Health recommends a conversation rather than a blanket rule for this age group.

Potential Benefits and Harms

Select a tab to compare what Ontario Health says about starting screening at 40.

  • Finding breast cancer early, when treatment has a better chance of working.
  • Ontario Health’s fact sheet estimates that, among 1,000 women who start screening at age 40, up to 9 breast cancer deaths could be avoided over their lifetimes.
  • Unnecessary biopsies: the same fact sheet estimates that up to 200 people out of 1,000 who start screening at 40 could have a biopsy they did not need.
  • Overdiagnosis: an estimated 12 people out of 1,000 could be diagnosed with a cancer that would never have caused them harm.
  • Additional tests and worry: a mammogram can lead to follow-up imaging that turns out to be normal.

These figures come from Ontario Health’s decision-support material, and they are estimates for groups of people, not predictions for you. Please read the full ages 40 to 49 page for the complete picture, including how these numbers compare with starting at age 50.

Before you decide, consider:

  • How do I feel about the possibility of follow-up tests, such as a biopsy, that might turn out to be nothing?
  • How important is it to me to find a cancer as early as possible?
  • Do I know about my family history of breast cancer, and have I shared it with my health care provider?
  • Have I completed a personal risk assessment, such as the My CancerIQ breast cancer questionnaire?
  • Would I rather decide now, or talk to my doctor or a Health811 navigator first?

Know Your Personal Risk with My CancerIQ

Ontario Health suggests completing the My CancerIQ breast cancer risk questionnaire, which takes less than 15 minutes. It is designed for adults 40 and over. My CancerIQ asks about things in your life that may affect your risk, then gives you personalized suggestions for reducing your chances of developing cancer. It does not predict whether you will get cancer, but you can save, print or email your results to refer to later or share with your doctor. Explore the whole tool at MyCancerIQ.ca and read about breast cancer risk factors and risk reduction here.

What If You Are at Higher Risk?

Some people have a higher chance of developing breast cancer, for example those with certain gene variants or a strong family history. People ages 30 to 69 who meet the criteria may be screened through the High Risk OBSP with a referral from a health care provider, with yearly mammography and breast MRI (or screening breast ultrasound if MRI is not medically appropriate). If you think you may be higher risk, do not wait until you decide about average-risk screening. Talk to your health care provider now.

Step-by-Step: Booking in Your Forties

  1. Read the fact sheet. Ontario Health’s fact sheet for ages 40 to 49 is available in English, French and 36 other languages. Open the ages 40 to 49 page and use the Resources for people ages 40 to 49 link in the right sidebar.
  2. Talk it through. Discuss your risk with your health care provider or a Health811 navigator.
  3. Find a location. Use the Ontario Health wait times tool to search by city or postal code.
  4. Book. Contact an OBSP location or call 1-800-668-9304. At Annex Medical Imaging you can reach us at (416) 531-1128.
  5. Repeat every 2 years if you decide screening is right for you.

What Happens at the Appointment?

A registered medical radiation technologist who specializes in mammography places your breast on a special X-ray machine. You will feel some pressure on your breast, similar to a tight blood pressure cuff. Do not use deodorants, antiperspirants, body lotions or talcum powders on the day of your appointment, because the metals in these products can show up on the X-ray picture. Our post on what to expect at your first mammogram covers the appointment in more detail.

Related Reading

  • Breast Ultrasound and Preparation
  • Breast cancer screening guidelines
  • Ultrasound vs. X-Ray vs. Mammogram: Which Imaging Test Do You Actually Need?

    • Frequently Asked Questions

    Do I have to get screened in my 40s?

    No. Screening is a personal choice for people ages 40 to 49. Ontario Health encourages you to discuss your risk and the potential benefits and harms with a health care provider or Health811 navigator, and then decide what is right for you.

    Do I need a doctor’s referral in my forties?

    No. If you meet the eligibility criteria, you can contact an OBSP location directly or call 1-800-668-9304. You do not need a referral or an order from your doctor.

    How often should I be screened if I decide to start at 40?

    Most people in this age group who decide to be screened should have a mammogram every 2 years.

    Is a mammogram safe?

    Mammograms are considered safe. They use a low dose of radiation, and Ontario Health notes that the benefits of screening and finding cancer early are more important than any potential harm from the X-ray.

    What if I notice a change in my breast before my next screening?

    Do not wait for your screening date. Changes such as a lump, dimpling, nipple changes, redness or skin changes should be reported to a health care provider right away.

    Is screening in my 40s free?

    Yes. The OBSP is publicly funded, so eligible participants do not pay for the screening mammogram.

    Where can I get the fact sheet in another language?

    The ages 40 to 49 fact sheet is available in English, French and 36 other languages. Open the ages 40 to 49 page and click Resources for people ages 40 to 49 in the right sidebar. Ontario Health’s resource hub also lists translated postcards, posters and screen savers.

    Key Takeaways

    • Ontario lowered the starting age for breast screening to 40 on October 8, 2024.
    • You can self-refer at 40 to 49 if you meet the criteria, with no doctor’s referral needed.
    • Screening every 2 years is recommended for those who choose it.
    • The decision is personal: weigh the benefits and harms with a health care provider or Health811 navigator.
    • Use My CancerIQ to understand your personal risk before you decide.
    Helpful Links and Resources

    OBSP appointment booking line: 1-800-668-9304.

    Book Your Screening Mammogram in Toronto

    Ready to book, or have questions about your eligibility? Contact Annex Medical Imaging at (416) 531-1128, or call the OBSP Appointment Booking Line at 1-800-668-9304. Learn more about mammography (OBSP) at Annex Medical Imaging.

    Book Your Appointment

    This article is for general information only and is based on information published by Ontario Health (Cancer Care Ontario) as of September 2026. It is not medical advice. Screening recommendations can change, so please confirm current details with the Ontario Health links above and speak with your health care provider about your personal situation.

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