We report a case of cholesterol granuloma, which involved the ethmoid sinus. Cholesterol granuloma arise from the mucosa and can recognized on plain films, tomograms and CT of the sinus as opacity, sometimes resembling a mucocele. The pathogenesis of the cholesterol deposits is suspected to be fatty degeneration of the connective tissue. Most of the crystal deposits are found in obstructed parts of the air cells. Radical operation seems to give absolute cure.