The potential of online games to become a major global business and the existence of limited related references led to the current study. In this study, Rogers's diffusion of innovation (DOI) theory is applied to investigate the principles for the adoption of online games in Taiwan. The findings suggest that relative advantages and compatibility both have a significant effect on the adoption of online games for purposes of amusement, with the former being more important for early gamers and the latter being regarded as more critical for later gamers. In addition, complexity is found to impede online game diffusion and is regarded as the most important facilitator.