The objective of this work was to evaluate the association between the average levels of blood pressure of 706 children in Porto Alegre with their nutritional state--body mass index (BMI), body fat percentage, waist circumference--and with their social-economic state. A prevalence of 12.3% (n=87) of high blood pressure was found. According to the BMI, 11% of the sample was obese. 47.7% belonged to the social class with an income less than two monthly minimum salaries. All of the correlations of the SBP (systolic blood pressure) and DBP (diastolic blood pressure) with variables in the nutritional state showed to be significant (p < 0.001). What ended up having a stronger association was the BMI and waist circumference with SBP (R = 0.27). This study made it possible to notice that the anthropometric indicator that best is related to the existence of high BP is the BMI along with the waist circumference. This seems to be an easy method that is noninvasive and of low cost to detect the risk of high BP in children and adolescents.