The purpose of this study was to explore the variables that might affect the learning outcomes of a serious game for disaster preparedness. Literature review in the field has revealed a number of variables that might have effects on the learning outcome with serious games, including: prior knowledge, in game guidance, gaming frequency, and playing skills. However, there has been no study on the relationships and effects between the types of knowledge (i.e., declarative, or procedural) used in serious games and the intended learning outcomes. Using disaster preparedness as a learning context, this study examines the two types of knowledge: (1) declarative (i.e., learners’ ability to retain facts and information), and (2) procedural knowledge (learners’ ability to perform actions and procedures), and their relationships with the learning outcomes of a serious game. The research question was: “To what extent do: prior knowledge, in-game guidance, and gaming frequency, predict the learning outcomes, in the forms of declarative and procedural knowledge of a disaster preparedness serious game?”