Problem solving can be a cognitively intensive undertaking; as design is characterized by ambiguity and unknowns, design problems in particular can be cognitively expensive. Few studies examine the evolution of cognitive load during the engineering design process and the linkages between sub-dimensions of cognitive load and design task outcomes. To address this issue, the goal of this work is to establish a relationship between cognitive load, design task, and design outcomes. Twenty participants were recruited to perform a design task where their mental workload was recorded at each stage of the design process. Their ideation and prototype outcomes were then evaluated to determine if there is a relationship between cognitive load, design task, and design outcomes. Results suggest that there is a significant difference in cognitive load experienced by the designer during each stage of the design process and while cognitive load is correlated with idea generation design outcomes, it may not be tied to prototyping design outcomes.