Mean systolic BP values gradually and significantly increase from the infancy to the adolescence. On the contrary, diastolic BP does not change significantly. No sex differences were found for mean values of both systolic and diastolic BP. The results of the longitudinal study (two years follow-up) have shown, for the two sexes, a significant increase in the systolic BP values, which parallels the ponderal growth. In particular, the greatest increment of the values was observed in the triennium 12-14 year, that is around the puberty.