BACKGROUND፡ Fostering critical thinking (CT) is one of the most important missions in medical education. Concept mapping is a method used to plan and create medical care through a diagrammatic representation of patient problems and medical interventions. Concept mapping as a general method can be used to improve CT skills in medical students. The aim of this study was to explore the effect of concept mapping on CT skills of medical students.METHODS: This quasi-experimental study was conducted on 100 second-year medical students which take an anatomy course. Participants were randomly assigned into a control group (lecture-based) and an intervention group (concept mapping). CT levels of medical students were assessed using the California Critical Thinking Skills Test. Data were analyzed using independent sample t-test.RESULTS: Before intervention, CT scores of the intervention and control groups were 6.68 ± 2.55 and 6.64 ±2.74, respectively, and after intervention, they were 11.64 ±2.29 and 10.04 ± 3.11, respectively. Comparison of mean score differences for both groups before and after intervention demonstrated that CT scores in the experimental group significantly increased after intervention (P=0.021).CONCLUSIONS: Medical students who were taught through concept mapping showed an increase in CT scores, compared with those in the control group. Medical students require effective CT skills in order to make sound knowledge-based assessment and treatment choices during patient care. Therefore, instructors and planners of medical education are expected to apply this educational strategy for developing CT skills in medical students.KEYWORDS: Concept Map, critical thinking skills, Medical education, medical students