Inverted papilloma arising from mucous membrane of the nasal cavity and paranasal sinuses is very rare benign neoplasm. Ward first described nasal papilloma in 1854, but its infrequent occurrence has delayed accurate understanding. This tumor was histologically benign neoplasm and clinically malignant, because it is locally invasive with extensive bone erosion at times and it shows a high incidence of local recurrence, and change of squamous cell carcinoma was sometimes found. Recently, the authors have experienced a case of inverted papilloma with focal squamous cell carcinoma change which occupied the right side of the nasal cavity and maxillary sinus in a 48 year-old male. The tumor mass was removed surgically through intranasal and Caldwell-Luc's approach, and then was treated with systemic administration of Bleomycin, local spray of 5-FU and radiotherapy (Co⁶⁰). We report our case with review of current literatures.