The incidence of tracheal stenosis following conventional tracheostomy has been reported as lying between one and 30 per cent. Methods used to assess the degree of stenosis include CT scanning, fibreoptic visualization and plain X-ray tomographs. The aim of this study was to assess the degree of stenosis in patients following percutaneous dilatational tracheostomy (PDT) using MRI scanning. This method has not been reported in the literature previously. Nine patients without symptoms of tracheal stenosis were studied for at least six months following PDT performed in the intensive therapy unit. The tracheas were assessed for scarring and stenosis using a three dimensional volume scanning MRI technique. Although scarring could be detected in the wall of the trachea and subcutaneous tissues of all patients, tracheal stenosis was not demonstrated at the insertion site or at the site of the cuff (p > 0.05). MRI scanning provides an excellent non-invasive method of assessing the tracheal lumen. Our patients who had undergone PDT do not appear to have any degree of post-operative stenosis.