Background: Postoperative sore throat is one of the most common complications afterendotracheal intubation. Both Ketamine and magnesium can block N­methyl­D­aspartic acid receptors and provide central and local analgesia. Objectives: To compare the efficacy of magnesium sulfate and ketamine gargle in preventionof postoperative sore throat. Methodology: A total of 90 patients posted for general anaesthesia with endotrachealintubation were enrolled in the study. Patients in ketamine group received ketamine gargle (50 mg) and magnesium group received magnesium sulfate gargle (20 mg/kg up to 30 mL normal saline) 15 minutes before the operation. Patient’s complaint of postoperative sore throat, and its severity were measured and recorded at baseline in recovery room, and then 0, 4, 8, 12 and 24 hours after operation. Results: To analyse the association of sore throat in two groups Chi square test wasused. p <0.05 was considered statistically significant Number of patients with sore throat were significantly lower in magnesium group compared to ketamine group at 0hr (p<0.001), 4th hr (p <0.001), 8th hr (p <0.001), 12th hr (p<0.001) and 24th hr (p =0.006) after the operation. Conclusions: Magnesium sulphate decreases sore throat and pain severity more effectively compared toketamine gargle.