In autopsy material naso-ethmoidal blocks were removed in 19 patients. None of the patients had a preceding rhinoscopy. Before removal, the maxillary and sphenoidal sinuses were opened and screened for polyps. After removal the total naso-ethmoidal complex was carefully examined for nasal polyps. The site of origin of the individual polyp was registered and documented photographically. Nine polyps were found in five patients, of which four had no history of asthma, allergy or sinusitis. Two patients had unilateral solitary polyps, three had polyps bilaterally. All polyps were found in the meatus. Eighty-nine per cent of the polyps were related to the clefts from the ethmoid. Polyps were not observed inside the ethmoidal and other paranasal sinuses.