In a 3-year period of prospective study, 250 pediatric patients with multiple trauma (injury to at least two body areas) had injuries scored by a modification of the Injury Severity Scale (MISS). This scale uses the categories and rankings of the Abbreviated Injury Scale—1980 (AIS—80) except for neurologic injuries. Neurologic injuries are scored by using a combination of the Glasgow Coma Scale (GCS) and other neurologic findings (presence of surgical mass lesion, pupillary light response, and oculocephalic reflexes). The MISS is calculated as the sum of the squares of the three most severely injured body areas. The mean MISS score was 27.8, with 38% of MISS scores ≥25 and 62% 6 hours duration); 80% of all deaths were due to neurologic injury and all but two deaths had some degree of head injury; the remaining 20% of deaths were due to chest and abdominal injuries. Patients with MISS grade 5 injury (critical, survival uncertain) had 73% mortality, while those with grades 4 and 3 injury had 8% and 2% mortality, respectively. The MISS serves as an accurate predictor of morbidity and mortality in pediatric trauma. The best predictors of outcome were an MISS ≥25 and the degree of neurologic injury.