Introduction: Myoclonic movement is not common side effect after general anaesthesia. Since we use various intravenous agents during general anaesthesia recently, it is troublesome to find out the exact cause of this neurologic complication. Patient concerns: A 28-year-old male patient without any past medical history underwent mandibular cyst enucleation surgery under general anaesthesia. Diagnoses: Sudden myoclonic movement confined to upper trunk and left upper extremity in recovery room after uneventful GA. Outcomes: There was no significant abnormality in electroencephalography or blood tests, which were taken after the event.