The number children and young people with high blood pressure has been increasing. The current lifestyle is one of the contributing factors to the disease. The most adverse is poor quality diet and excessive intake of salt. Further, the energy expenditure is lower, e.g. due lack of physical activities. Many children and young people do not have enough information about the risks of high blood pressure and its prevention. It is critical to identify groups with a risk of hypertension, i.e. children and young people with the so-called ?high normal? blood pressure. At the beginning we set four objectives: to learn the blood pressure measuring techniques suitable for children ? using digital and mercury tonometers, to find 25 ? 30 children with the ?high normal? blood pressure, to instruct nurses, particularly in the primary care, about the correct technique of blood pressure measurement in children and to compare the values of blood pressure measured with mercury and digital tonometers. The research was conducted in basic and secondary schools in České Budějovice and in a pediatric surgery. The researched group consisted of children and young people aged 13 ? 18. To achieve the first objective we measured blood pressure in 613 children with a digital tonometer and to achieve the second objective we measured blood pressure in 50 children both with mercury and digital tonometers. The results have been presented in form of tables. We found out that it was not necessary to examine more children, as we had expected, to get a sample group of 30 children with the ?high normal? blood pressure. Further, we found out that there was no significant difference between the values measured with a mercury tonometer and with a digital tonometer. The results have shown that it is essential to use the correct technique for blood pressure measurement in children. Based on our findings we have developed an educational material for nurses.