Background Football (soccer) is the leading sport for participation among Nigerian youths. Studies on youth football injuries and their risk factors in Nigeria are lacking. Objective To assess the risk and pattern of lower extremity (LE) injuries in Nigerian male youth football players. Design A retrospective cohort study. Setting Sub-elite youth football. Participants The study involved 706 players (aged 17.67±1.11 years [14-19 years]) from 36 teams in the Premier League and League I of a Nigerian youth football league. Interventions: A structured questionnaire based on the FIFA Medical and Research Centre consensus for studies relating to football injuries was administered to players at a pre-season screening programme. Main Outcome Measurements: Information collected from the players included occurrence of time-loss LE injuries in the past 1 year, injury type, location, severity and exposure type. Furthermore, descriptive data on potential risk factors such as age, level and position of play, leg dominance and total number of matches played were documented. Results A total of 227 players sustained 307 time-loss LE injuries (range, 1-6 injuries) with an overall 1-year prevalence rate of 32.5%; equivalent to 1.4 injuries per player per year. There was no significant difference in injury prevalence between the Premier League and Division I players (P=.659). Injuries sustained were mostly located on the ankle (45.6%) and the knee joints (27.8%). Moderate injuries (48.5%) were mostly reported and more injuries were sustained during matches than training (P<.001). Exposure to high frequency of matches (>50 matches per year) (OR=2.49, P=.002) was significantly associated with injury occurrence. Conclusions There is a high risk of moderate and severe LE injuries among Nigerian male youth footballers, however, pattern of injuries are mostly consistent with literatures on football injuries. This study suggests the need for injury prevention and rehabilitation interventions for players.