In recent years, the market for mobile games has become the most important part in the mobile content industry. The purpose of this study are to identify a causality between flow and customer loyalty in mobile games and to identify the factors by which flow is influenced. Mobile game players were surveyed and the data were statistically analyzed empirically. Empirical results indicate that four independent variables such as game design, challenge, skill and feedback have impacts on the flow. And customer loyalty is significantly influenced by the flow. Based upon the statistical results, some useful guidelines for mobile game development and market penetration strategies are also provided.