As engineering education has moved from didactic instruction to more learner-centered methodologies, new and innovative techniques are being used to teach engineering student. One such technique is problem-based learning. Problem-based learning (PBL) has its roots in medical field, where it has been used for over a century to portray the complex and ill-structured nature of medicine and to develop complex professional reasoning in medical students. This paper, part of the 2010 ASEE Annual Conference and Exposition proceedings,  describes an investigation of problem-based learning on undergraduate electrical engineering students' conceptual understanding. Fifty-five students enrolled in an electrical engineering course at a Mid-western university participated in this student. The study utilized a within- subjects A-B-A-B research design with traditional lecture as the baseline phase and problem- based learning as the experimental phase of the study. Participants completed pre-post tests surrounding the four topics covered in the study. Results suggested that participants' learning gains from problem-based learning were more than learning gains from traditional lecture.