The aim of the study was to confirm whether there is a secular trend towards the early onset of puberty without an early onset of menarche. The study included a total of 1,266 subjects, 771 females and 495 males, with an age range between 5.9 and 18.2 years. In all subjects height, percentile of height, weight, percentage of overweight, bone age and pubertal stages were evaluated. On the basis of pubertal stage the population was subdivided into Tanner’s corresponding classes. The obtained data for the female population showed a stabilized onset of puberty compared to the last decades and prolonged length of the pubertal period. Pubertal development in males, instead, did not appear to have changed over the last decades. The study is in line with American studies; the earlier onset of puberty verified in the last decades has slowed prolonging the length of the pubertal period. The specific mechanisms implicated in sexual maturation are not yet well known and need further studies.