Airway obstruction of endotracheal tubes may occur during general anaesthesia. A case is reported where endobronchial intubation and inflation of the cuff caused herniation into the left bronchus before the malpositioning had been corrected. This led to a cuff herniation that caused airway obstruction at the end of anaesthesia. The regional overinflation of the tubes cuff could be reproduced by a model by other tubes of the same type. Malpositioning of endotracheal tubes may cause cuff herniation that potentially leads to acute airway obstruction.