The study aimed to compare remifentanil, magnesium sulfate, and dexmedetomidine for intraoperative hypotension, bleeding volume, and recovery time in endoscopic sinus surgery and tympanomastoidectomy (TM). A double-blind clinical trial enrolled the patients undergoing endoscopic nasal sinus surgery and TM at Amirkabir Hospital (Arak, Iran), who were randomly assigned into three groups dexmedetomidine (DEX), remifentanil (REM), and magnesium sulfate (MgSO4) to which we intravenously administered 1 μg/kg DEX, an intravenous dose of 1 μg/kg REM, and 40 mg/kg of intravenous MgSO4, respectively. The blood loss, blood pressure (BP), heart ratio (HR), oxygen saturation (SaO2), and recovery time were recorded. Significant differences were found statistically in bleeding rates among all groups (P = 0.0001). The least amount of blood loss (very mild bleeding) was observed at 82.85% in the DEX group. BP and HR were lower in this group than those in the other groups. While recovery score was significantly different in the three groups (P = 0.007), the recovery time was the highest in the DEX group, while the least in the REM group. Based on the present results Dexmedetomidine seems to better prevent from bleeding than the others. Moreover, DEX can cause lower BP and HR in subjects with lower propofol administration, but the recovery time is longer. This study was registered by IRCT2017021114056N11 in Iranian Registry Clinical Center.