Chronic paranasal sinusitis is one of the most common diseases in the field of otolaryngology. Caldwell-Luc's operation and intranasal ethmoidectomy with or without surgical microscopes have been performed frequently. With the development of nasal endoscopes and improved understanding of nasal pathophysiology, endoscopic sinus surgery has become a popular procedure because of complete eradication of diseased sinus mucosa with less postoperative complications. Three hundred and eighty procedures performed in 190 consecutive patients who had undergone endoscopic sinus surgery were analyzed prospectively in terms of preoperative endoscopic and ostiomeatal unit(OMU) CT findings, and postoperative outcome of symptoms, postoperative endoscopic findings, complications and patient's satisfaction. Overall, 182(95.8%) patients benefithed from the procedurce. Patients with nasal obstruction preoperatively showed the greatest improvement. Synechia was the most common complication in endoscopic sinus surgery. No serious intra- and postoperative complications were not observed.