Autopsy findings in 3, 185 cases of death due to traffic accidents obtained from all institutions belong to the Medico-Legal Society of Japan between 1990 and 1994 were analyzed statistically. The results are summarized as follows: 1) The annual number of autopsy cases related to traffic accidents was stable and accounted for 10% of all autopsy cases examined. The autopsy cases also accounted for only 6% of all deaths due to traffic accidents. Cases requiring judicial autopsy are few despite the fact that deaths due to traffic accidents are considered deaths resulting from professional negligence. 2) The purposes of autopsy were, in a decreasing order of frequency, (1) to examine whether the accident was a hit-and-run case, (2) to examine whether the case was multiple accidents, and (3) to clarify the relationship of death with the accident. 3) According to the age, those who were involved in accidents while they were on foot overwhelmingly aged 70 years or above, and those who were involved in accidents while they were riding motorcycles were predominantly in their teens to the 20's. Concerning the situation of the accident, run-over cases, were frequently those in their 40's, and collision cases were predominantly those in their 70's. Among those who died in cars, the drivers were most frequently those in their 50's, followed by those in their 20's. 4) The degree of external and internal injuries was compared. About half the victims sustained severe injuries both internally and externally, and the remaining half sustained mild external injuries and severe internal injuries. Run-over cases generally had severe injuries both internally and externally, but collision cases tended to have mild external injuries and severe internal injuries. 5) The most frequent cause of death was brain injury, followed by loss of blood and traumatic shock. 6) Tire marks were observed in 23% of the run-over cases, and they were observed in the head, face, neck, and thoracoabdominal region in most cases. 7) Of the collision cases, collision injuries were observed in 55.6%, and the sites of collision injuries were the crural and femoral regions. 8) Of those who died in the car, about 46% were the drivers. 9) Deaths while driving due to internal causes accounted for 3% of all autopsy cases who died in traffic accidents, and ischemic heart disease was the most frequent of the internal causes. 10) Concerning injuries caused by safety devices, 3.5% of the drivers and 4.4% of non-driver passengers were injured by the seat belts, and 3.9% of those who were riding motorcycles were injured by the helmets. 11) Alcohol was detected from 47.7% of the cadavers examined, and the alcohol level was 0.5 mg/ml or above in 19% of those driving and 50.2% of those on foot. 12) Stimulants were detected in 5 (3.8%) of 132 cases examined, and thinner was detected in 17 (13.0%) of 131 cases examined.