This study was a retrospective chart review of hospital records and autopsy reports of 499 children nine years old or younger in-volved in motor vehicle collisions from 1994 to 1998. The objective was to evaluate the frequency and severity of injuries as a function of age, re-straint use, and seat position. We found that 33% of the children were unrestrained and 20% were improperly restrained. Unrestrained children had the highest mean Maximum Abbreviated Injury Scores (MAIS) and Injury Severity Scores (ISS), accounted for 70% of the fatalities, and had the highest incidence of head in-juries. Although most of the head injuries were superficial, 80% of the fatalities were the result of a head injury. Improperly restrained children had the highest frequency of abdominal injuries. Regardless of restraint use, the back seat was associated with fewer head injuries and lower mean MAIS and ISS scores compared to the front seat. Also, properly restrained children in the front seat had lower mean MAIS and ISS scores than unrestrained children in the back seat, suggesting that restraint use is more beneficial than seat position.