Due to the presence of pain during nasogastric tube (NGT) insertion and related complications and lack of positive clinical response of nasopharyngeal anesthesia with lidocaine and the related side effects and limitations in ketamine and intravenous midazolam, this study aims to determine the efficacy of oral midazolam in relieving pain in the patients requiring NGT insertion. Methods: A randomized, triple-blind clinical trial was performed on the patients in the Emergency Department of Zanjan Valiasr and Mousavi Hospitals in Iran, who were nominated for NGT. In each group, 100 patients were examined. Two milligram syrups of midazolam and placebo were administered 20 min before the procedure. In two groups, the pain based on the Visual Analog Scale and satisfaction rate of patients during the NGT insertion were compared. The data were analyzed through the SPSS software version 16.0. Findings: There was no statistically significant difference in the demographic characteristics of two groups. Despite the effects of potential confounding variables, the cause of the referral and indication of NGT, as well as the use of midazolam syrup, had a significant relationship with the outcome, so that midazolam group experienced less pain. The mean and standard deviation of the examined outcomes (feeling of pain and satisfaction with NGT insertion) was statistically significantly different in the midazolam group as compared to the placebo group (P = 0.001). Conclusion: Midazolam was effective in decreasing pain and increasing the satisfaction of patients after NGT insertion. This manuscript is registered in Irct. com with code IRCT20110629006922N4.