Background: Functional Endoscopic Sinus Surgery (FESS) has become a standard modality of the chronic rhinosinussity disease that is refractory to medical treatment. Objectives: To apply a FESS to assess the efficacy based on clinical symptoms and nasal endoscopy. Materia and method: Patients with chronic rhinosinussity disease after adequate medical therapy, aged from 12 to 71 years old.