A case of intraoperative tracheostomy tube obstruction is reported. The clinical features and the chain of events leading to the diagnosis of cuff herniation are presented. The different mechanisms of herniation are discussed. In the present case we speculate that a manufacturing defect together with nitrous oxide diffusion into the cuff caused dilatation and herniation of the latter which led to obstruction of the distal tube lumen. We draw attention to this rare but life-threatening complication.