Abstract
            Introduction: We investigated the effect of education on the knowledge and decision-making of  medical interns, based on emergency severity index (ESI) triage. 
   Methods: In this pre and post-interventional study, 155 medical students who were passing  their internship course of the emergency ward were enrolled with convenience sampling from  July 2018 to June 2019. The students were randomly classified into two groups (103 cases and  52 controls). The questionnaire was administered twice in the control group (before initiating  the educational class and 1 month after completion of the educational course). In the case  group, the test was conducted at three times (before the educational class, immediately after  completion of classes, and one month after completion of the educational course). The data  were analyzed by using t test and ANOVA.  
  Results: The total score of the students in the case group in the pre- and post-training stage  (posttest 1) was 17.13±4.26 and 24.93±3.20 respectively, which had a significant difference  (P<0.001). The total score of the students in the posttest 2 was 23.38±5.66. Statistical test  showed that there was a significant difference between the two groups of the students in terms  of the test in the one month after completion of the educational course (P<0.001) except for  under triage (P=0.236). 
   Conclusion: The findings indicated that education based on ESI triage was effective on the  knowledge and decision-making of medical interns. Based on the results of this research and  given the importance of triage, theoretical and practical educational courses are proposed for  medical students