Army trainers are increasingly turning to alternative training methods to exploit low-cost, technology-based solutions to fill critical training gaps and increase training effectiveness. One technological approach that has received increased interest over the last decade is game-based training. Army agencies and organizations have recognized that games have the potential to augment military training for both individuals and collectives. However, compared to more traditional training effectiveness and design studies, empirical investigation of game-based training is in its infancy. The existing body of research is only starting to provide insight as to how well game-based training works relative to other methods, not why or when to use it. Therefore, the purpose of this research was to investigate the general effectiveness of game-based training using principles generated through decades of research on training effectiveness. Also, the research literature indicates that training effectiveness is determined by the training program (e.g., the game), the trainee (e.g., personal characteristics), and the situational context of the training (Campbell & Kuncel, 2001). Therefore, this study also focused on the conditions under which game-based training is effective. This paper describes the methods, measures, and results of an evaluation with 165 Soldiers participating in game-based training as units. Pre- and post-training measures were administered. Results indicate that game-based training influenced training effectiveness. Contextual variables such as level of preparation prior to the training also influenced the effectiveness. The results of this evaluation provide important points for all training designers to consider when using game-based training.