Polypoid changes are the most frequent pathologic manifestations in the mucous membranes that line the nasal cavity and the paranasal sinuses. The etiology of polyp formation is still widely debated, but none of theories is universally accepted. The authors studied 152 patients (261 sides) who had visited our hospital with complaints of nasal symptoms were diagnosed as having nasal polyp and operated on from Dec. of 1990 to Sep. of 1992. and We identified the site of origin of the polyps with diagnostic and operative endoscope. The results were as follows : 1) The highest frequency of age was the 3rd decade. 2) The sex ratio, male vs female, was 1.3 : 1. 3) The majority of nasal polyps were multiple and bilateral. 4) Frequent complaints were nasal obstruction, rhinorrhea, hyposmia, and headache in its declining order. 5) Of the patients who received nasal polypectomy, 79% had chronic paranasal sinusitis and 26%, allergic rhinitis. 6) Of the patients who received nasal polypectomy, 34% had a past history of receiving nasal polypectomy. 7) The most frequent sites of origin were the contact areas of the uncinate process and the middle turbinate and the ethmoidal infundibulum (82%). There were, additionally the anterior aspect of the ethmoidal bulla and hiatus semilunaris (43%), in the frontal recess (22%), in the turbinate sinus (22%), in the bulla (17%), in the lateral sinus (14%), in the posterior ethmoid (12%), in the head or free margin of the middle turbinate (8%), and septum, inferior turbinate, and others in its declining order.