The authors conducted two studies to explore online game players' flow experiences and positive affect. Our findings indicated that online game are capable of evoking flow experiences and positive affect, and games of violent or nonviolent type may not arouse players' aggression. The players could be placed into four flow conditions: flow, boredom, anxiety, and apathy, as determined by level of perceived challenges and skills. The majority of players entered the flow condition when playing violent or non-violent online game. The path analysis results suggested that violent online games may have a significant but indirect effect on positive affect via flow experience mediation. (Contains 2 figures and 1 table.)