OBJECTIVE To evaluate injuries occurring during the preseason in youth soccer players. DESIGN Prospective cohort study over 1 preseason. SETTING 2009-2010 preseason. PARTICIPANTS Subjects were 912 youths aged 12 to 19 years. ASSESSMENT OF RISK FACTORS The club's medical staff prospectively recorded all injuries. A reportable injury was defined as by the consensus statement on soccer injuries. Estimated injury rates per 1000 hours of exposure during the preseason period were calculated. MAIN OUTCOME MEASURES Injury rates (injuries per 1000 hours of soccer exposure) during preseason practices by age group, as well as prevalence, severity, and type of injuries. RESULTS Total incidence was 2.5 injuries per 1000 hours of exposure. Incidence of match and training injuries were 6.7 and 1.8 injuries per 1000 hours (P = 0.02), respectively. Injuries were sustained by 7.2% of players during the preseason, and 79% of the injuries involved the lower limbs, of which 23% were located to the thigh. Muscle strains and contusions were the most common injuries and external trauma the main cause. CONCLUSIONS No age-related trend in the incidence of preseason injuries was found. During the preseason training period, athletic trainers should expect a majority of muscle strains, especially in the thigh region.