Background & aim: There is closed noisy environment and the patient needs to be immobile for a substantial time for successful conduction of magnetic resonance imaging (MRI). We can use propofol, but it can cause hypotension, respiratory depression and loss of airway reflexes. Dexmedetomidine causes conscious sedation without respiratory depression. The aim of our study was to compare the efficacy of dexmedetomidine versus propofol, in conducting MRI in children. Methods: This prospective, randomized, comparative study was conducted after getting approvals and written and informed assent. Total 60 children of 2-10 years age, ASA grade I and II, undergoing MRI were randomized into: group D: received injection dexmedetomidine i.v. infusion @0.8- 1.0 ug.kg-1 over 10 min, followed by continuous infusion @0.4-0.6 ug.kg-1,h-1 or group P: received injection propofol @1 mg.kg-1 bolus i.v., followed by continuous infusion @100 ug.kg-1.min-1.The sedation level was measured using the Ramsay Sedation Score (RSS) every 1 minute until the score of 5 was achieved. The rescue sedation was administered as injection ketamine 1-2 mg.kg-1 i.v. Patients were allowed to breathe spontaneously. Quality of MRI was evaluated using 3-point scale. Any episode of adverse event was noted. Quantitative data was analyzed using student t test and qualitative, using chi square test. Results & conclusion: The mean time for onset and the duration of sedation was longer in group D than group P, (P=0.004 and 0.030 respectively). Total 40% patients requiring rescue sedation in group D and 10% in group P. Hence propofol is better than dexmedetomidine for sedation in children undergoing MRI.