<div><p>ABSTRACT Introduction: Doping control is an important means for preventing the use of illegal substances and methods in sports. Objective: This study investigated the self-reported use of illegal substances among young Brazilian students in the Youth School Games, the main sporting event among school-aged athletes in Brazil with almost 2 million students during all the phases. Methods: Cross-sectional study with athletes of the Youth School Games 2006 aged 14-17 years. The subjects were randomly selected and completed an anonymous questionnaire about substances use. Chi-square test was used for comparison of proportions between different variables on self-reported use of substances. Univariate and multivariate analyzes and logistic regression were performed. Results: Among the 402 athletes (aged 14-17) who volunteered to participate, the results showed high prevalence of alcohol (35.8%), nutritional supplements (39.1%), and tobacco (5.4%). Regarding illegal drugs and doping, 1.7% reported the use of stimulants, 2.2% illicit drugs, 0.5% anabolic steroids, and 1.7% hormones and other similar substances. Moreover, a different use of stimulants was found (especially Judo and Table tennis), medications (especially Judo and Chess) and dietary supplements (especially Swimming and Judo, with over 50% reported use). Conclusion: The present study suggests that the use of substances among young athletes is similar to the results found among adult Olympic athletes as per International Olympic Committee and World Anti-Doping Agency, especially regarding the use of dietary supplements, anabolic steroids, and stimulants according to data collected by other studies. We consider that the findings of the present work indicate the need for specific efforts to monitor, prevent, and control use of substances among school athletes in big events and competitions, such as this research on doping in the Youth School Games.</p></div>