Availability of valid and usable measures of cognitive load involved in learning is essential for providing support for cognitive load-based explanations of the effects predicted and described in cognitive load theory as well as for general evaluation of learning conditions. Besides, the evaluation of cognitive load may provide another indicator of levels of learner expertise in addition to performance scores. As mentioned before, due to the available schematic knowledge base, more knowledgeable learners are expected to perform their tasks with lower mental effort than novices. Even though simple subjective rating scales remain the most often used measures of cognitive load imposed by instructional materials, new more sophisticated techniques are being developed, especially in multimodal environments associated with performance of complex cognitive tasks. This chapter provides a brief overview of traditional, as well as some novel methods for measuring and evaluating cognitive load. Some recently developed approaches to using these measures in estimating instructional efficiency of learning environments are also discussed.