Instructional simulation and games are usually used as substitutes for actual equipment, processes, real-life problems, and social situations. They allow observing outcomes of different learner actions and steps without involving actual hardware and people. They also provide environments for practicing important skills in an efficient (in terms of cost and time) way. From a cognitive load perspective, using actual equipment or human actors may not necessarily lead to the acquisition of expected knowledge and skills. High cognitive load involved in operating the equipment itself, performing required procedures, interacting with other people, especially when allowed time is constrained, may inhibit learning. In such high load situations, limited cognitive resources would be left for actual learning. Instructional simulations and games allow modeling such processes without time limitations and other cognitive constrains. Instructional simulations may also allow representing abstract knowledge structures and processes that are difficult to observe in real conditions. They may enhance the development of abstract thinking and problemsolving skills by offering environments for exploring and testing hypotheses. Many available instructional simulations and games represent mostly exploratory learning environments with limited guidance for learners. From a cognitive load perspective, any random exploratory or search procedures may impose excessive levels of working memory load thus interfering with meaningful learning (see Chapter II for more details about basic principles of cognitive load theory). Therefore, optimizing levels of instructional guidance represents the most important means of managing cognitive load and enhancing learning outcomes in such environments. This chapter starts with examining the role of simulations as instructional technology tools and describes means of enhancing instructional effectiveness of simulations and games. Then the chapter discusses how to evaluate cognitive load in simulations using concurrent verbal reports. Some issues of cognitive load associated with instructional applications of mobile technologies are considered at the end.