Background: This study aims to propose the method of staging of chronic sinusitis based on functional symptoms and contribute to united diagnosis of the gravity of chronic sinusitis. Patients and method: 121 patients suffering from chronic sinusitis studied by cross sectional descriptive study. Results: Staging of chronic sinusitis based on functional symptoms: degree II was 55.4 percent, degree III 30.6 percent, degree I 10.7 percent, degree IV 3.3 percent
based on nasal endoscopy: degree I showed 38 percent, degree II 33.9 percent, degree III 20.7 percent, degree IV 7.4 percent
based on cr scan: degree II occupied 43.8 percent, degree I 22.3 percent, degree IV 17.4 percent, degree III 15.7 percent. Staging of chronic sinusitis based on functional symptoms evaluated the gravity of sinusitis higher than endoscopy but lower than cr scan. If degrees I and II were unified to minor stage, and degrees III and IV were unified to serious stage in order to compare between 3 methods, we found that these 3 methods classified equivalently in staging of chronic sinusitis. Conclusions: The study proposed the fairly simple method in staging of chronic sinusitis based on functional symptoms and determined correlations of functional symptoms, endoscopy and CT scan for diagnosis of gravity of chronic sinusitis.