Context Despite the popularity of soccer at the male first-division youth level, data on the incidence of injuries in Brazil are limited. Objective To prospectively study the injury profile of male first-division youth soccer players during 1 season (January to December 2017). Design Descriptive epidemiology study. Setting Data compiled at a youth soccer academy. Patients or Other Participants The study involved 228 players between 10 and 20 years old from a first-division Brazilian soccer academy. Main Outcome Measure(s) Injury incidence rate was reported as the number of injuries divided by overall exposure (training and match hours) multiplied by 1000. The rate ratio (injury incidence rate during matches in relation to training) was also calculated. Time-loss injuries (ie, physical complaints sustained during soccer matches or training that resulted in a player being unable to take part in soccer training or match play) during the season were recorded. Results A total of 187 injuries were documented in 122 players (65.2%). During the season, 100 389 hours of exposure (5995 hours of match play and 94 394 of training) were registered. The overall injury incidence rate was 1.86 per 1000 hours. In total, 4792 days were lost from soccer activities. The majority of injuries were noncontact thigh muscle disorders and ankle sprains. Injury incidence was greater in matches than in training, and the oldest age group (under 20 years old) had the highest injury incidence rate in matches, while the under 17-year-old group had the highest injury incidence rate in training sessions (22.48 and 3.05 per 1000 hours, respectively). Conclusions Muscle injury incidence rates observed among Brazilian soccer athletes under 20 years old were similar to those reported in professional players. Preventive measures are recommended to reduce injury rates. Additionally, the number of injuries incurred during training was high compared with match play, and training programs need to be assessed so that injury prevention can be improved.