The aim of this double-blind clinical trial study was to evaluate the intravenous infusion effect of dexmedetomidine to control bleeding during functional endoscopic sinus surgery in 2016 in Imam Khomeini Hospital, Ahwaz. Inclusion criteria included patients aged between 18 and 60 years of age, ASA class I, II and exclusion criteria included diabetes mellitus, coagulation disorders, kidney and liver dysfunction, cerebrovascular disease, cardiovascular disease, high blood pressure, asthma, COPD, psychiatric disease, drug allergy, taking beta-blockers, heart rate less than 55. Samples were randomly divided into two groups of 30 individuals in intervention and control groups. Induction was carried out by using 1 mg midazolam, 2 μ/kg fentanyl, 2mg/kg propofol, 0.5 mg/kg atracurium. For maintenance purposes, 50% N20-O2 was combined with 100µ/kg/min propofol, 0.2 µ/kg/min remifentanil. 1μ/kg dexmedetomidine was injected within 10 minutes in the intervention group then 0.5 μ/kg/hr of dexmedetomidine infusion began. Also, normal saline was used in the control group with the volume equal to a dose of dexmedetomidine. Then the blood pressure and heart rate were measured every 5 minutes up to the reversal of neuromasular blockade. The bleeding rate was also examined and recorded based on the weight of gases and volume of the suction tank, wake-up time from reverse injection until eyes opening, intraoperative drug consumption and the severity of nausea and vomiting within two hours of recovery. Dexmedetomidine as well as propofol and remifentanil infusion was discontinued respectively 15 and 5 minutes before the end of surgery. Patents were recovered from anesthesia using 0.05 mg/kg neostigmine and 0.02 mg/kg atropine.