We examined by use of scanning microscopy the healthy looking tracheal mucous membrane 25 mm from the cancer lesions. The small pieces were taken during the initial routine tracheostomy before the laryngectomy. In 21 examined patients there was one woman. One patient did not smoke tobacco and did not drink alcohol. 19 were farmers and workers. Two had other professions. The normal tracheal mucous membranes were found in 6 patients, 2 of them were farm workers. In the remaining group there were abnormal appearance of cilia or complete lack of them, being replaced by the plain epithelium layer. In one case after cobalt therapy the mucous membrane was completely destroyed.