The tracheas of 37 tracheostomized patients (31 men and 6 women) were studied in connection with obduction. Twenty-six patients had been intubated before tracheostomy and 29 of the tracheostomized patients were treated with a respirator. At autopsy, the damage caused to the tracheal wall by the cuff was studied macroscopically; the finding was photographed for later investigation and samples were taken from the damaged area for microscopic examination. The purpose of the study was to determine the damage caused to the tracheal wall by the low-volume cuff we have used during the last 4 years. The cuff diameter was nearly the same as that of the trachea. The injuries were grouped according to their extent and depth as mild, moderate or severe, and the groups contained, respectively, 5, 12 and 20 patients. It seemed that cuff pressure played a greater part in causing damage than the duration of cuff strain. Factors in the clinical condition of patients, like hypotension, uraemia, respiratory infections, sepsis and use of steroids, may have had an effect on the development of damage. The injuries caused by the cuff used are so severe that there is every reason to use instead the low-pressure, high-volume cuff, which has been shown to cause less damage, whenever long-term treatment is involved.