Scaffolding students' problem solving and helping them to improve problem solving skills are critical in instructional design courses. This study investigated the effects of students' uses of a digital mapping tool on their problem solving performance in a design case study. It was found that the students who used the digital mapping tool performed better than those who did not use the tool in providing arguments when defining the problem and justifying the solutions. The results indicated that digital concept mapping could facilitate students' ill-structured problem solving. In this study, guide map was used. Future research may examine the use of free style map in problem solving.