Inverted papillomas in the nose and/or paranasal sinuses exhibit a high recurrence rate, and an association with malignancy. Early diagnosis and aggressive surgical therapy are thus essential. Seventeen cases of inverted papilloma seen at Saitama Cancer Center over a 17-year period were reviewed. Common presenting symptoms, the primary papilloma sites and the results of surgical treatment were as follows. 1) Almost all patients complained of nasal obstruction. The usefulness of nasal biopsy of the tumor was confirmed, with 12 cases being diagnosed as having inverted papilloma pre-operatively. Inverted papilloma without squamous cell carcinoma caused osseous thinning, but did not destroy the bone. 2) It was found that the primary site of the papilloma involved the lateral wall of the nasal cavity. Lateral Rhinotomy was therefore recommended as a standard treatment. 3) The recurrence rate was 1/12 after Lateral Rhinotomy. Two cases had complaints associated with the Lateral Rhinotomy, nasolacrimal duct stenosis, and a scar in the median corner of eye. 4) Only one case had concomitant squamous cell carcinoma in the nose and maxillary sinus. This patient received chemo therapy, radiation therapy and finally maxillectomy, but the inverted papilloma recurred several times. Six years later, squamous cell carcinoma recurred and lead to this patient's death.