Over the last four years, we have encountered four cases of cholesterol formation in the nasal polyp in our hospital. These patients had no previous history of nasal and/or paranasal surgery. Cholesterol clefts were noted in the acidophilic fluid of the cystic space of the nasal polyp in three of the four cases. One case was included in which the predominant histological picture was of cholesterol clefts with a surrounding foreign body giant cell reaction and granulation tissue formation. The origin of cholesterol in these lesions was obscure. It is presumed that the relatively insoluble cholesterol was dissociated from the lipoprotein complex derived from fluids and/or destroyed cellular elements in the cystic nasal glands of the polyp. The pathogenesis of the cholesterol granuloma in the nasal polyp was discussed as compared with that of the middle ear.