This study investigated the relationship between violent video games and children's mood. A total of 71 children aged 8 to 12 years played a paper-and-pencil game, a nonviolent video game, and a violent video game. Results indicate that arousal, as measured by heart rate and self-reported arousal, increased significantly after playing the violent video game, as compared with the other two game conditions, with girls reporting more arousal than did boys. There was no significant increase in aggressive mood scores for either boys or girls after playing the violent game. Positive mood, as measured by positive affect, showed no significant increases or decreases after playing either video game. However, positive mood, as measured by general mood, showed a significant increase after playing the violent game for both boys and girls, but only as compared with the paper-and-pencil game. Results are interpreted in terms of social learning and cognitive information processing theories of aggression.