Inverted papilloma arising from the nasal cavity and paranasal sinuses is an uncommon epithelial tumor which is characterized by histologically benign tumor, but clinically malignant nature due to excessive bony erosion, high recurrence rate and an assoiation with malignancy. The incidence of malignancy associated with papilloma from 2% to 53%. Careful follow-up is very important because of the high recurrence rate following incomplete removal of papilloma and the possibility of malignant transformation in such recurrences. Selection of therapy depends on an accurate radiologic assessment of the extent of the tumor. The authors reviewed 43 cases of pathologically diagnosed inverted papilloma from 1986 through 1986. The results were as follows : 1) The male was more frequently affacted(M : F=4 : 1) and the average age of patients was 57 years. 2) The most common presenting symptom was unilateral nasal obstuction. And the nasal discharge, headache and postnasal drip were frequently presented. 3) The sixteen cases had the past history of previous nasal surgery. 4) The lateral nasal wall and combined involvement of maxillary sinus or ethmoid sinus were the most frequent site of tumor. 5) The lateral rhinotomy with media maillectomy were performed in nine cases and Caldwell-Luc's operation and ethmoidectomy in six cases. 6) Recurrence was noted in ten cases(23.7%). 7) One case of squamous cell carcinoma was found in a patient who had three previous operations. And two cases had concomitant squamous cell carcinoma with tansitional zone between benign inverted papilloma and squamous cell carcinoma.