Mammothon is a one-day breast screening marathon hosted by six Regional Cancer Programs across Ontario. The event encourages Ontario women aged 50+ who are overdue or who have never had a mammogram to take action, make the time, and get a mammogram.

Known as Ontario’s largest breast-screening marathon, Mammothon has 53 Ontario Breast Screening Program (OBSP) sites participating across the province. Together, we have a combined goal to screen 1000 women in just one-day!

Click here to find a participating OBSP site near you and learn how to book your mammogram. Every participating site has something fun, exciting and unique to offer women getting their mammogram on May 4!

The OBSP provides high-quality breast screening free of charge for Ontario women.