Overweight during youth is a large-scale public health issue. Engaging in regular physical activity generally reduces weight status. The hypothesis of the study is that organized sport plays an active role in maintaining a correct body weight during youth. The purpose of this study is to trace growth charts by height, weight, and body mass index (BMI) to be applied to the youth sports population. A retrospective study was conducted on 14,700 young athletes (10,469 males and 4231 females) aged between 6 and 18 years from surveillance carried out during the pre-participation screening of sports eligibility. The calculation of the prevalence of overweight and obesity was also performed. The new percentiles for the youth sports population show BMI values at 18 years 21.9 kg/m2 for males and 20.7 kg/m2 for females at the 50th percentile. The male sample shows 12.3% of the subjects were overweight and 1.5% were obese, while the female sample shows 9.8% are overweight and 1.1% obese. The higher prevalence of excess weight is evident up to 12 years old in both sexes and then gradually decreases. The development of the new specific growth charts for the youth sports population could reduce the risk of error in identifying the correct weight status of young athletes.