Heat-moisture exchanger (HME) is an inexpensive and effective device used to prevent respiratory complications that can be caused by endotracheal tube insertion during general anesthesia. But, HME can increase airway resistance and be occluded by the patient's secretions. Whether a HME could be occluded by clear fluids such as condensate in the airway circuit is not certain yet. In vitro, a case of HME occlusion by normal saline was reported. We report a case of HME obstruction by distilled water came from the heated wire circuit which was unintentionally connected to the HME.