A closed-claim analysis of anesthetic-related deaths and permanent injuries in the dental office setting was conducted in cooperation with a leading insurer of oral and maxillofacial surgeons and dental anesthesiologists. A total of 13 cases occurring between 1974 and 1989 was included. In each case, all available records, reports, depositions, and proceedings were reviewed. The following were determined for each case: preoperative physical status of the patient, anesthetic technique used (classified as either general anesthesia or conscious sedation), probable cause of the morbid event, avoidability of the occurrence, and contributing factors important to the outcome. The majority of patients were classified as American Society of Anesthesiologists (ASA) status II or III. Most patients had preexisting conditions, such as gross obesity, cardiac disease, epilepsy, and chronic obstructive pulmonary disease, that can significantly affect anesthesia care. Hypoxia arising from airway obstruction and/or respiratory depression was the most common cause of untoward events, and most of the adverse events were determined to be avoidable. The disproportionate number of patients in this sample who were at the extremes of age and with ASA classifications below I suggests that anesthesia risk may be significantly increased in patients who fall outside the healthy, young adult category typically treated in the oral surgical/dental outpatient setting.