The body mass excess (BME) in children and adolescents is a serious and commonly recognized problem of public health. The aim of the presented study was evaluation of the frequency of occurrence of improper anthropometric parameters, such as arterial blood pressure, waist circumference, and the WHtR in children with excessive body mass, and to indicate the importance of performing systematic measurements of basic anthropometric parameters and blood pressure in early prevention of overweight and obesity. The study covered a total number of 488 children aged 13-15. In all children in the study, measurements were performed of blood pressure and basic anthropometric parameters (body height and weight, waist circumference) with the use of standard equipment. The BMI index was applied to evaluate the general fatness. Metody wczesnej profilaktyki otyłości wieku rozwojowego 189 Overweight or obese children constituted 31.39% of the total number of children examined. In children with excessive body mass an increased waist circumference was observed in 52.27% of girls and 81.13% of boys. Elevated systolic and diastolic blood pressure in girls was 36.36% and 27.72, respectively, whereas in boys these values reached 49.1% and 30.18%, respectively. The frequency of occurrence of visceral obesity according to the WHtR>0.5 criterion, was higher in boys – 58.49% than in girls – 29.54%. The increased frequency of overweight and obesity at developmental age requires wide-scale preventive measures. Simple anthropometric parameters characterising the degree and type of fatness are of great diagnostic importance in the detection of early disorders associated with obesity