Background: Ondansetron is a 5HT3 receptor blocker and has multifaceted action like sodium channel blocker and µ - opioid agonist. Objective: To compare the efficiency of ondansetron pre-treatment in alleviating pain caused by propofol during induction of general anaesthesia with placebo. Material & Method: In this randomized controlled trail 120 patients of ASA grade I & II undergoing elective surgery were included and divided into two equal groups A & B by using lottery method. Each group comprised of 60 patients. In group A two ml 0.9 % normal saline and in group B, 2 ml ondansetron (4mg) given intravenously. In both groups propofol was given in a dose of 2.5 mg / Kg intravenously. Results: The mean age of patients in group A was 29.95 ± 4.79 year and in group B was 30.30 ± 4.87 year. Majority of patients 67(55.83 %) were between 18 to 30 year of age. Out of 120 patients. 63 (52.50 %) were ASA I & 52 (47.50 %) were ASA II. Efficacy of group A (placebo) was seen in 11 (18.33 %) while in group B (ondansetron) was seen in 56 (93.33 %). Conclusion: Ondansetron pre-treatment in alleviating pain cause by propofol is very effective. Keywords: Pain, ondansetron, propofol, general anaesthesia.