Background: There has been no accurate report of mortality rate and malpractice in our surgery departments, however, these reports may lead to increased mortality probability, further stress on physicians and patients, and also distrust on physicians. Autopsy is the most reliable diagnostic technique, and its educational value is noticeable, too. We have evaluated the autopsy and mortality rate in department of surgery, Modarres General Hospital, between 1990 and 1999. Materials and methods: It was an existing data study. The cause of death was classified in accordance to Gordon Guidelines to five subdirectories: Error in Judgement (EJ), Error in Diagnosis (EO), Error in Technique (ET), Error in Management (EM), and Patient's Disease (PO). Results: During the study period, a total of 14041 patients were hospitalized, of whom 12441 (88.6%) underwent operation. The overall mortality rate was 3.9% (488 patients). Autopsy was performed on 390 cases. The cause of death was as below: EM (14.5%), EJ (11.6%), ET (10.6%), and EO (7.1 %). 59.6% of the patients were died due to their own disease (PO). Error in Diagnosis has shown significantly lower probability (p<0.0266). Conclusion: Our findings are comparable to the western societies, which demonstrate a unique educational performance. Having the same studies performed in other surgery departments, we could promote the educational level of residency training program.