The process of atherosclerosis may begin developing during childhood. Multiple studies show that risk factors for coronary artery diseases are present in children and adolescents. Risk factors that have been shown to track are obesity, high blood pressure (BP), physical inactivity and smoking.The schools are an especially effective and efficient system for providing health education for children. Both classroom - based and risk - based interventions had positive effects on physical activity and knowledge: however, the results from the large group, classroom - based approach showed stronger trends and were much easier to implement in the school system.The major purpose of the school - based project of our Healthy Heart Study was to determine whether a school - based intervention could improve healthy heart knowledge in third, fourth and fifth grade children in Shahr-e-kord.