In a random sample of adolescent schoolchildren (n=204) we assessed functional state of endothelium of brachial artery by test with reactive hyperemia. The data obtained was compared with values of arterial pressure and nutritional status of these adolescents and results of questionnaire survey of their parents concerning heredity and lifestyle. In 12.4% of examined subject values of flow mediated vasodilation were abnormal (less than 10%). We found that these abnormalities were most often observed in adolescents with hereditary predisposition to cardiovascular diseases, elevated arterial pressure, excess of fatty mass, inactive way of life.