Inverted papilloma of nose and paranasal sinuses is pathohistologically benign but clinically malignant because of its local aggressiveness, high recurrence rate and milignant transformation. Various theories about its origin were presented with controversy. Recently the theory that the origin of inverted papilloma was squamous metaplasia of nasal mucosa arising in nasal polyp was strongly supported. Goodman reported that he found inverted papilloma in 5% of nasal polyp. Here we report a patient with inverted papilloma which is supposed to arise in nasal polyp.