The incidence of the abuse of illicit drugs in sport may be a useful indicator of the extent of the phenomenon among the youth population. Many drugs of abuse are included in the WADA (World Anti-Doping Agency) Prohibited List, and are therefore routinely tested for in antidoping controls. This study presents the data obtained in tests carried out in the period 2003- 2007 at the Antidoping Laboratory of Rome, on 44781 samples analysed. The methods used are those developed by the Laboratory for routine antidoping analyses. The percentage of positive test results ranges from 1.1 to 2%, with a high incidence of stimulants and drugs of abuse. The substance most frequently found is THC metabolite, which accounts for 0.2-0.4% of the total, followed by cocaine metabolites, accounting for 0.1%. Other stimulants found are ephedrines, carphedon, modafinil, and anorexic compounds such as phendimetrazine and norfenfluramine. No amphetamines or amphetaminelike designer drugs have been detected. These data may be indicative of the widespread incidence of cocaine and cannabis abuse among the young Italian population, bearing in mind that the phenomenon is underestimated in this study, due to the fact that drugs of abuse are investigated only in samples involved in competitive sport, and especially to the fact that people doing such activities take more care of their health and are subject to greater control in their behaviour and habits with respect to the 'normal' population.