Background: Although functional endoscopic sinus surgery (FESS) allows better visualization during surgical dissection, the occurrence of intraoperative bleeding may hinder this advantage. Controlled hypotension is recommended to decrease intraoperative bleeding, and it could be achieved by multiple medications that have some undesirable side effects. Dexmedetomidine, an alpha-2 agonist, is known to induce hypotension and its intranasal administration is understudied. The current trial aims to evaluate its beneficial impact on intraoperative and postoperative parameters during FESS. Patients and methods: A prospective, randomized study was conducted on eighty patients, who were divided into two equal groups; Group D received 1 ml (100 µg) dexmedetomidine nasal drops, and Group F received fentanyl (1.5 µg/kg) as nasal drops. Both medications were administered after installing local anesthesia. Results: We noted no significant differences between both groups regarding demographic variables and operative time. However, the severity of intraoperative bleeding, heart rate, and mean blood pressure decreased markedly in Group D. The sedation level was comparable between the two groups. As regards the analgesic profile, Group D showed a marked decline in postoperative pain scores (two and three hours after surgery) with a significant prolongation of the time to the first rescue analgesic. However, the percentage of patients requiring rescue analgesia was comparable between the two groups. Conclusion: The intranasal administration of dexmedetomidine during FESS has several advantages, manifested by the decrease in intraoperative heart rate, MAP, and bleeding severity and better postoperative analgesic profile compared to fentanyl.