Background: Functional endoscopic sinus surgery [FESS] is a well-established therapeutic option for intractable CRS. In case of major bleeding, risk of complications such as meningitis, blindness, intracranial injury, cerebrospinal fluid [CSF] leakage and the duration of surgery increase. Aim of work: The present work aims to compare between the efficacy of dexmedetomidine and glyceryl trinitrate in inducing controlled hypotension to improve the quality of the operative field during FESS under general anesthesia. Materials and Methods: In our study, the number of patients was 40 which were divided randomly into two groups: (a) Glyceryl trinitrate group: twenty patients received Glyceryl trinitrate (GTN group). (Dexmedetomidin group: twenty patients received Dexmedetomidine (DEX group). Results: It was confirmed that dexmedetomidine causes significant stable hemodynamics, excellent surgical field and significant surgeon satisfaction compared to glyceryl trinitrate. It also causes sedation effect so less extra doses of fentanyl were used. Conclusion: We concluded that during ambulatory FESS, dexmedetomidine is more effective than glyceryl trinitrate for providing controlled hypotension and rendering an excellent surgical field with higher surgeon's satisfaction score and lesser analgesic requirement without major hemodynamic alteration.