Tracking of blood pressure (BP) over an 8-year period between the age of 6 and 14 years and the effect of weight, height, BMI and weight gain has been studied in a population of school children in Jerusalem (n = 533). Pearson's correlation coefficients were 0.65 for weight, 0.61 for height, 0.32 for systolic BP and 0.29 for diastolic BP over an 8-year period. Children maintaining their percentile rank for weight or BMI showed higher correlations than those increasing or decreasing their percentile rank. Girls' menarcheal status did not have a significant effect on the level of BP at 14 years of age. The prevalence of significant and severe BP as defined by the NHLBI Task Force was 1% at 6 years and 0.4% at 14 years. The predictive value of the BP at 6 years for 14 years of age was low even for those with hypertension levels: for SBP 16-33% and for DBP 0-37%. Based on the present study and others, large scale screening of BP is not recommended, rather community based programs aimed at modifying health behaviour in order to prevent development of cardiovascular risk factors and associated morbidity and mortality should be introduced.