Background: Hoarseness, cough, and sore throat are the most prevalent complications after removing patients’ endotracheal tube and general anesthesia. Various methods have been proposed to reduce these complications after intubation. Objectives: The present study aimed to assess the effect of softening the endotracheal tube with normal warm saline on reducing post-intubation complications such as sore throat and hoarseness. Methods: This double-blind, randomized controlled trial was performed on patients undergoing general anesthesia at Rasoul Akram and Firoozgar hospitals in Tehran, Iran. In the present study, 58 patients were randomly divided into 2 groups of 29 patients. All patients underwent the same premedication with fentanyl and lidocaine. Anesthesia was induced with propofol and atracurium. Three to 5 minutes after atracurium injection, the laryngoscopy test was performed. Randomly, some patients were intubated with a thermally softened endotracheal tube, and some were intubated with a normal tube. At the end of the operation, when the spontaneous breathing was adequate, and the patients could carry out oral instructions, the endotracheal tube was removed immediately after suctioning. All patients were evaluated for sore throat and hoarseness before discharge from recovery and 24 hours after surgery. The obtained data were analyzed using SPSS software package version 25. Results: The mean incidence of sore throat in recovery in the intervention group (20.7%) decreased compared to the control group (75.8%). Moreover, the mean incidence of hoarseness in the intervention group (17.2%) decreased in comparison to the control group (41.4%, P < 0.029). Based on the data of our study, we observed that 24 hours after surgery, the mean incidence of sore throat among the patients of the intervention group was significantly lower compared to the control group, where patients in the intervention group did not feel any sore throat (P < 0.002). We also observed that 24 hours after surgery, the amount of hoarseness in the intervention group (3.4%) also decreased compared to the control group (24.1%, P < 0.022). Conclusions: Based on the results, it can be concluded that thermal softening of the endotracheal tubes with normal warm saline before intubation could be significantly effective in decrement of sore throat and hoarseness during recovery and 24 hours after surgery.