Background: Chronic Rhinosinusitis and nasal polyps proposed the criteria for diagnosis of chronic rhinosinusitis in adults as 12 or more weeks of persistent symptoms (nasal blockage, discharge, facial pain, reduction of smell) and signs (polyps, mucopurulent discharge, mucosal edema) with no complete resolution. This debilitating disease causes negative impact on quality of life (QOL) of patients. Functional endoscopic sinus surgery (FESS) is the mainstay of surgical treatment for patients and improves QOL of patients. Objective: to assess improvement in quality of life (QOL) after functional endoscopic sinus surgery through questionnaire sino-nasal outcome test (SNOT)-22. Methods: The present study was conducted on 51 patients in ENT department of Mission General Hospital, Nilphamary, Bangladesh. The study period was from January 2020 to March 2020. All the patients with age ≥18 years who failed to respond to medical therapy (3 months) and underwent functional endoscopic sinus surgery (FESS) were included in the study. SNOT-22 questionnaire was used to assess the improvement. Results: In our study, preoperative SNOT scores were higher (54±8.05) but after FESS they reduced significantly at 1st (16.47±5.51), 3rd (13.86±4.19), 6th months (12.9±8.05) post operatively. Chronic rhinosinusitis (CRS) with nasal polyposis group had greater mean difference of SNOT-22 scores (43.93) between preoperative period and 3 months postoperative period than patients grouped as CRS without nasal polyposis (41.47). Conclusions: We concluded that FESS is the best surgical intervention for chronic rhinosinusitis. It significantly improves the quality of life of patients of chronic rhinosinusitis.