Background and aims Approximately 16% of all sports injuries in the Netherlands are caused by outdoor soccer. A cluster-randomised controlled trial has been designed to investigate the effectiveness and cost-effectiveness of an injury prevention programme ('The11') for male amateur soccer players. The injury prevention programme The11, developed with the support of the World Football Association FIFA, aims to reduce the impact of intrinsic injury risk factors in soccer. Methods Teams playing at first-class amateur level in two districts in the Netherlands are participating in the study. Teams in the intervention group were instructed to apply The11 during each practice session throughout the 2009e10 season. All participants of the control group continued their practice sessions as usual. All soccer-related injuries and related costs for each team were systematically reported online by a member of the medical staff. Player exposure to practice sessions and matches was reported weekly by the coaches. Also the use of The11 during the season after the intervention season will be monitored. Discussion Our hypothesis is that integrating the The11 exercises in the warm-up for each practice session is effective in terms of injury incidence, injury severity, healthcare use, and its associated costs and/or absenteeism. Prevention of soccer injuries is expected to be beneficial to adult soccer players, soccer clubs, the Royal Dutch Football Association (KNVB), health insurance companies and society.