AIM To analyze the relationship between blood pressure in childhood and adolescence and different variables including gender, age, weight, height, body mass index and sexual maturation. METHODS Cross-sectional study conducted in 1278 boys and girls aged 6 to 18 years old. Two blood pressure measurements were obtained. Mean value in the two measurements was obtained for each of the pressures: systolic (SBP), diastolic IV (DBPIV) and diastolic V (DBPV). Simple and multiple regression analysis were done to evaluate association between variables. RESULTS 14 years 0.33; SBP boys > 14 years 0.34; DBPIV 0.25; DBPV 0.24) and height (SBP 6-13 years 0.33; SBP girls > 14 years 0.23; SBP boys > 14 years 0.29; DBPIV 0.25; DBPV 0.24) than for age (SBP 6-13 years 0.27; SBP girls > 14 years 0.17; SBP boys > 14 years 0.15; DBPIV 0.23; DBPV 0.22) for each of the blood pressures. Multiple regression analysis demonstrated a significant association between body mass index, height and SBP in the group of boys and girls aged 6-13 years old. No other significant associations were obtained. CONCLUSIONS Blood pressure values in childhood and adolescence show a positive association with growth and maturation variables. It's of capital importance to considerate not only age, but also height, weight and body mass index when evaluating the blood pressure value of a child.