Problem-based learning (PBL) is one of the most commonly used educational methods in medical schools of different countries. By working through this method, students think critically, generate ideas, and acquire the knowledge and skills required to become a doctor.This study aimed to compare problem-based learning with lecture-based learning in the education of medical students.This crossover interventional study was conducted on 40 medical students in pediatric ward of Zanjan University of Medical Sciences. All of the students were enrolled in the study and divided into two groups by simple randomization. Then two topics in pediatric courses were chosen. One of the topics was presented as LBL for the first group and as PBL for the second group. The other topic was presented as PBL for the first group and as LBL for the second group.The median score of the exam was higher in the intervention group compare to the control group for both topics. However, the difference was not statistically significant. Students preferred problem-based learning over lecture-based learning because of motivation boost, a higher quality of education, knowledge retention, class attractiveness, and practical use.Students' knowledge was similar in both methods.