The Department of Health is issuing pedometers to schoolchildren across the country in a bid to reduce childhood obesity.
The "Schools on the Move" programme hopes to encourage children to become more active.
Between this September and next March, 45,000 pedometers will be distributed to schoolchildren at 250 schools to help battle childhood obesity.
A pilot study of pedometers has shown they are particularly effective at encouraging less active children to get fit.
Children will be able to use a specific website to track their pedometer progress and set targets.
Public Health Minister Dawn Primarolo said: "Three out of ten boys and four out of ten girls area not achieving the recommended physical activity levels.
"Pedometers are a fun and simple way for children to develop an interest in keeping fit and get into the habit of exercise."
She adds that children interested in getting fit often persuade their families to become more active as well.
Chief Executive of the Youth Sport Steve Grainger added: "By bringing physical activity into the classroom in a fun and innovative way, young people can be shown the importance of maintaining a health lifestyle and the positive impact being active will have on them throughout their lives."