This study aimed to assess knowledge and skills in a respiratory physiology course in traditional versus problem-based learning (PBL) groups in two different medical schools. Two different undergraduate medical schools were selected for this study. The first medical school followed the traditional [lecture-based learning (LBL)] curriculum, and the second medical school followed the PBL curriculum. Sixty first-year male medical students (30 students from each medical school) volunteered; they were apparently healthy and of the same age, sex, nationality, and regional and cultural background. Students were taught respiratory physiology according to their curriculum for a period of 2 wk. At the completion of the study period, knowledge was measured based on a single best multiple-choice question examination, and skill was measured based on the objective structured practical examination in the lung function laboratory (respiratory physiology). A Student's "t"-test was applied for the analysis of the data, and the level of significance was set at "P" less than 0.05. Students belonging to the PBL curriculum obtained a higher score in the multiple-choice question examination ("P" = 0.001) and objective structured practical examination ("P" = 0.0001) compared with traditional (LBL) students. Students in the PBL group obtained significantly higher knowledge and skill scores in the respiratory physiology course compared with students in the traditional (LBL) style of medical schools.