Inverted papilloma, characterized by tendency to recur, capacity to destroy, and association with malignancy, was first reported by Ward in 1854. In Korea only some cases have been reported, but there were few reports of clinical studies. Authors compared the various clinical manifestations in pursued 29 cases of 35 cases of inverted pailloma of the nasal cavity and paranasal sinuses, which had been confirmed histopathologically and treated at the department of otolaryngology, Seoul National Universal from January, 1977 to May, 1990, and reached the following results ; 1) The cases comprise 26 males and 3 females, and the age ranges from 36 to 72 years. 2) In descending order, the clinical symptoms were nasal obstruction, rhinorrhea, postnasal drip, hyposmia and so on. 3) In 14 cases, medial maxillectomy via degloving or lateral rhinotomy approach was done, and in 12 cases Caldwell-Luc operatoion was performed. 4) In only one case the lesion was limited in the nasal cavity, and the rest (28 cases) extended to one or more paranasal sinuses. In one out of 29 cases, the lesion involved bilaterally. Coexisting malignancy (squamous cell carcinoma) was found in three patients. 5) Postoperatively, 7 cases (medial maxillectomy 4 cases, Caldwell-Luc operation 3 cases) recurred and 6 patients complained of epiphora.