Nasogastric (NG) tube placement for gastrointestinal decompression is a common procedure for most major surgeries in the operating rooms. However, it could cause life-threatening complications in some difficult cases if it is not correctly placed in the stomach and recognition of misplacement is not prompt. We report a case of inadvertent endobronchial misplacement of NG tube in a patient intubated with double-lumen endotracheal tube for anesthesia. The NG tube slipped past the high-volume-low-pressure cuff of double-lumen endotracheal tube accidentally, resulting in airway-leakage and ventilatory failure. Traditional methods such as aspiration of gastric contents or auscultation of gastric insufflation air for confirmation are unreliable to exclude misplacement of NG tube. We suggest that using capnography to detect misplacement of NG tube in the trachea or facilitating NG tube insertion by videolayrngoscope (GlideScope) could be considered in the operating rooms to avoid complications.