Respiratory inductive plethysmography is a non-invasive method of assessing breathing patterns that requires an airway connection for calibration. In previous studies an endotracheal tube was used to establish this connection. We employed a single position graphic calibration technique for gain calculation using a conical face mask in place of the endotracheal tube, thus eliminating the need for sedation and topical anaesthesia. Thirteen studies were completed on seven lambs. Validation of gains was performed by comparing volumes obtained simultaneously by respiratory inductive plethysmography and integrated pneumotachography. Total study time ranged between 5 and 10 min for each calibration procedure. Our results suggest that the conical mask can be used to perform accurate and time-efficient calibration of the respiratory inductive plethysmograph in the spontaneously breathing non-sedated lamb and eliminates the need for endotracheal intubation.