Ludwig's Angina is the term given to the symptoms resulting from infection of the submandibular space and is characterized especially by extreme edema of the floor of the mouth. Airway obstruction and respiratory difficulty is common due to edema of the mouth, tongue, and the glottis, from mediastinitis due to spread, or from septicemia or pneumonia. Thus it is necessary for the anesthetist to attend to specific management of airway maintenance. A 49 year old male had an operation for incision and drainage under balanced anesthesia. After the operation, posthypoxic myoclonus due to anoxia for three minutes appeared while in the recovery room. The patient, controlled by oxygen supply and diazepam and antiepileptics, has recovered from the seizures, but has not recovered from intention myoclonus and speech disturbance, which are slowly improving. This report describes this case of posthypoxic myoclonus following anesthesia and reviews the literatures.