Cognitive load refers to the total amount of mental activity imposed on working memory at one time, and the premise of the Cognitive Load Theory is that human working memory is limited and only a few elements of information can be held and processed in working memory at a time. Consequently, presenting too much information simultaneously may overload working memory and diminish the efficiency of information processing. The purposes of this paper is to suggest five design principles for developing multimedia-based learning materials that do not cognitively overload learners, and based on these principles to evaluate multimedia-based instructional materials. The paper concludes with suggestions for future research and development of multimedia-based learning materials.