This clinical study was undertaken to evaluate the etiology and management of the decannulation difficulty. During the period from Jan. 1971 to Feb. 1982, we have experienced 26 cases of decannulation difficulties in the Seoul National University Hospital. The results of this study are as follows : 1) This study revealed that the most susceptible age group to the decannulation difficulty was the 2nd and 3rd decade and under the age of ten. 2) The most common cause of decannulation difficulty was the growth of granulation tissue in the subglottic area, cicatrical stricture in the subglottic area and dislocation of tracheal wall in order. 3) We can decannulate the tracheal cannula in the most of the affected individuals (84.6%). The most excellent methods were found to be the T-tube insertion and silastic stent insertion. The time interval between the insertion of T-tube or stent and removal was two to eight months.