Purpose. Providing dental treatment for intellectually disabled patients is usually performed under general anesthesia. This randomized double-blinded parallel clinical trial study aims to evaluate the effect of dexmedetomidine on the blood pressure and recovery conditions of these patients. Methods. Fifty intellectually disabled patients without systemic problems or physical disability were recruited. The anesthetic regimen included 5 mg/kg of sodium thiopental, 0.8 mg/kg of atracurium, and 1-2 mcg/kg of fentanyl; and 100 mcg/kg/min propofol for maintenance. The intervention group received additional 2 mcg/kg/h dexmedetomidine by infusion. The control group received equal amount of 0.9% saline. Patients’ blood pressure, duration of anesthesia and recovery, types of dental treatments and agitation levels in recovery were recorded. Results. Systolic blood pressure fluctuated in control group (P = 0.032 between 15 and 30 minutes and P = 0.009 between 45 and 60 minutes), while it did not significantly alter in the intervention group (P = 0.942). The diastolic blood pressure did not significantly change neither in dexmedetomidine (P = 0.094) nor in the control group (P = 0.277). Patients’ agitation levels were significantly lower in dexmedetomidine group at 15 (P = 0.015) and 30 (P = 0.003) minutes post-operatively. The use of dexmedetomidine did not significantly elongate the stay in recovery (P = 0.194). Conclusion. Dexmedetomidine can be used to improve intra-operative blood pressure stability and to decrease post-operative agitation without lengthening recovery time.