The forced oscillation technique (FOT) is the method of choice for assessment of respiratory tissue mechanics. A laryngeal mask airway (LMA) is increasingly used to secure the airways in subjects under sedation or general anesthesia. While FOT is routinely performed using an endotracheal tube (ETT), the accuracy of information about airway and tissue mechanics obtained with FOT using a LMA has not been characterized. Therefore, we compared the mechanical parameters obtained with FOT using LMA and ETT in rabbits.