Bleeding during functional endoscopic sinus surgery always been a challenge for the quality of surgical field for surgeons. This study aimed to evaluate the effect of local nasal desmopressin premedication on blood loss and the quality of surgical field in functional endoscopic sinus surgery. This study was conducted on 90 patients with chronic rhinosinusitis who were candidate for endoscopic sinus surgery. They were randomly assigned to two study groups. One group received a single puff of local desmopressin (10μg) in each side of nasal cavity 30min before the surgery and the other received normal saline instead. Blood loss and the quality surgical field were determined in 15, 30, 60 and 90min during the surgery (scoring by BOEZAART grading system). All data were analyzed. Blood loss was significantly lesser in the desmopressin group (mean ± SD, 16.289 ± 5.605ml) than in the control group (24.289 ± 5.2722ml, P < 0.001).Surgeons were more satisfied with the surgical field in the desmopressin group than control group in all cutoff points (15, 30, 60, and 90min during the surgery, P < 0.001). No side effects were observed using local desmopressin. Premedication with local desmopressin can reduce bleeding effectively and clear the surgical field during functional endoscopic sinus surgery.