Given the increasingly dominant role of video games in the mainstream entertainment industry, it is no surprise that the scholarly debate about their impact has been lively and well attended. Although >100 studies have been conducted to examine the impact of violent video games on aggression, no clear consensus has been reached, particularly in terms of their long-term impact on violent behavior and aggressive cognitions. This study employs a first-ever longitudinal laboratory-based experiment to examine longer-term effects of playing a violent video game. One hundred thirty-five participants were assigned either to the treatment condition where they played a violent video game in a controlled laboratory setting for a total of 12 hours or to the control group where they did not play a game. Participants in the treatment group played Grand Theft Auto IV over a period of 3 weeks and were compared with a control group on the posttest measures of trait aggression, attitudes toward violence, and empathy. The findings do not support the assertion that playing a violent video game for a period of 3 weeks increases aggression or reduces empathy, but they suggest a small increase in proviolence attitudes. The implications of the findings are discussed.