Thousands of women are taking part in Race for Life events at Meridian Park in Cleethorpes and East Homes Field in Ilkley.
The Race for Life is the UK's largest women only fund-raising event. Since Race for Life began six million participants across the UK have raised over £457 million to fund the work of over 4,000 researchers, doctors and nurses dedicated to helping more people beat cancer.
Read about progress made in cancer research since Race for Life began in 1994.
Developments from cancer research have led to an overall drop of around 16% in the death rate from all cancers since Race for Life began.
Find out how to take part in a Race for Life here.