Introduction: Anesthesia deaths are rare, while deaths due to surgical or other risk factors are more frequent. The goal of this analysis is to evaluate risk factors associated with postoperative mortality. METHODS: We have analyzed 34,200 surgical patients between 1990 and 1996 through records of anesthesia. The following informations were recorded; age of patients, physical status, site of operation, time of death, primary cause of death. RESULTS: The results are as follows; 1) Of 34,200 surgical patients, 119 died in the hospital. 2) The postoperative mortality rose progressively with age and was highest above 70 years. 3) Within 48 hours, the mortality was 36.1% of total deaths, declined progressively thereafter. The patients who had head operations exceeded 45% of deaths during this period. Eight days after the operation the mortality rate was 34.2% of total deaths and the patients who had an elective operation of the abdomen were 60.8%. 4) 34.2% patients of the total deaths had brain damages. Of these, 79.5% showed physical status V and had an emergency head operation and 47.5% were 50~60 years of age. 17.5% and 13.2% of deaths were due to sepsis and respiratory insufficiency and 48.6% of these two categories were physical status II, III and had an elective operation and 55.5% were above 60 years. CONCLUSION: The postoperative mortality was highest in the patients who had an emergency head operation and primary cause of death was brain damage. The patients of above 60 years, had a physical status II, III, had an elective abdominal operation were succeptable to sepsis and respiratory insufficieny.