Endotracheal intubation has been a routine practice in general anesthesia and is accepted by anesthetiste and surgeons as an integral part of airway management during anesthesia and operation. Paradoxically however, there have been several cases of obstruction of the airway which occurred due to endotracheal intubation. The authors experienced two cases of airway obstruction due tendotracheal and endobronchial techniques, using tubes with malfunctioning cuffs. The lumen of an endotracheal tube was collapsed by intracuff pressure, shortly after inflation of the cuff and resulted in extremely high airway resistance. In the other case, gradual leakage of air from the distal cuff of a Carlens tube led to collapse of the distal cuff. This promoted the movement of blood, secretions, and pus from the diseased right lung to the normal healthy left lung in association with the left lateral recumbent position, which in turn resulted in total airway obstruction.