Sedation of children for MRI is usually associated with inadequate or failed sedation because of difficulty in achieving complete immobility while maintaining hemodynamic and respiratory stability. 30 children each in two groups Group D receiving intravenous (iv) dexmedetomidine a potent, highly selective α2adrenoreceptor agonist and Group P receiving iv propofol were compared for efficacy in MRI sedation. Dexmedetomidine was effective in 78.5% of cases with 21.5% of children required additional medications. Side effects occurred in approximately 25% of cases, bradycardia (3.9%) and hypotension (18.4%) that resolved spontaneously. In group P, the onset of sedation, recovery, and discharge time were significantly shorter than in group D (P< 0.05). The level of consciousness was the same in both groups at the time of discharge. The duration of drug infusion was not different between groups (P> 0.05). 100% of the children in both treatments completed their MRI scans without interruption or interventions (i.e., no failures) and without complications. Heart rate and systolic blood pressure changes were transient and statistically significant, but not of sufficient magnitude to warrant interventions.