BACKGROUND: 137 anesthesia-related adverse outcome cases were registered by civil courts, criminal courts, police departments, and district health care centers with the Korean Society of Anesthesiologists between November 1994 and October 2002. These cases were analyzed according to type of event causing the adverse outcomes (death, brain damage, disability). METHODS: 137 adverse outcome cases were classified into obstetric and gynecologic, orthopedic, surgical, and other cases. Also, based upon a review of medical records, anesthesia records, autopsy findings, investigation records and the decisions of civil courts and criminal courts, the cases were classified into four categories; e.g. problems due to anesthetic management, preexisting diseases or preoperative patient conditions, anesthetic agents or anesthetic techniques, and operating procedures. RESULTS: 1) 45 cases were associated with problems due to anesthetic management (ventilatory failure, drug overdose, etc). 2) 39 cases were associated with problem due to preexisting diseases (cardiovascular disease, cerebrovascular disease, diabetes mellitus, etc) or preoperative patient conditions. 3) 27 cases were associated with problems due to anesthetic agents or techniques (nerve injury, malignant hyperthermia, etc). 4) 26 cases were associated with problems due to operating procedures (massive bleeding, embolism, etc). CONCLUSIONS: The most common type of damaging event causing an anesthesia-related adverse outcome was connected with anesthetic management. Therefore, it is mandatory to prepare adequate anesthetic monitoring equipment and to monitor patients thoroughly, to ensure safer perioperative anesthetic management.