Introduction: Cardiopulmonary arrest remains a major health problem and a cause of sudden death in the world. Immediate help to save the life of cardiac arrest patients is very important. Cardiopulmonary resuscitation training in schools could be an effective and affordable idea to develop those skills in the society. The aim of this study was to assess the effect of cardiopulmonary resuscitation training on Basic Life Support knowledge and performance among the students.Method: In this quasi-experimental study, a total of 40 6th grade students from both sexes were selected randomly from Larschools from 2013 to 2014. Validity and reliability of the personal characteristics, knowledge questionnaire, checklist, and Half-body Cpr Training Manikin, “personal characteristics” and “knowledge” questionnaire, and checklist were completed before cardiopulmonary resuscitation training. The training session included theoretical and practical sessions. Right afterthe intervention and one month after the training, “knowledge” questionnaire and checklists were completed again. Then, data were analyzed using SPSS version 22.Results: The results showed significant difference in mean scores of knowledge and performance of students before, immediately, and one month after the training (P<0.001). After one month, mean score of knowledge and performance decreased in comparison with immediately after training (P<0.001) but remained significantly higher than before training (P-value<0.001). Although immediately after the training, there were no significant difference in the score of knowledge and performance of students according to their parents education, and mother’s occupation (P>0.05), but there was a significant difference in the mean score of performance of students according to their father’s occupation immediately after the training (P<0.05). Also, there was a significant difference in the mean score of performance between body mass index groups immediately after the training (P<0.05).Conclusion: The results of this study emphasizes the need for planning and implementing cardiopulmonary resuscitation courses among elementary school students; as well as, regular implementation and retraining courses in order to maintain and promote public health using school pediatric nurses.