BACKGROUND Trauma is the leading cause of death in children, accounting for half of all deaths in patients between birth and 18 years of age, and is the cause of a significant number of hospital admissions. We reviewed our experience at a Level I pediatric trauma center with a 2-level trauma activation (TA) system for mobilization of personnel over a 3-year period. The aim was to assess severity of injury of the trauma patients, resource use, and outcome. METHODS After obtaining institutional review board approval, a retrospective analysis of all trauma patients between January 2006 and December 2008 was performed. Data analyzed included number of admissions, level of TA (STAT vs ALERT), mechanism of injury, intensive care unit (ICU) admission, injury severity score (ISS), need for operative intervention, and survival. RESULTS In 3 years, there were 4502 patients entered. Trauma activation was initiated in 1315 patients (29.2%), divided between 211 STATs (4.7%) and 1104 ALERTs (24.5%). Mean patient age was 5.9 ± 4.1 years, 65% of the patients were boys, and blunt trauma accounted for 92% of the admissions. An ICU admission was required in 736 (16.3%) of the entire group, whereas 502 (38.2%) patients in the TA group were admitted to the ICU(1). The 154 STAT (21%) and 348 ALERT (47%) patients accounted for 68% of all ICU admissions(1). An ISS listed as severe (16-24) or very severe (>24) was found in 468 (10.4%) and 232 (5.2%) patients, respectively. An ISS listed as 16 or higher was found in 144 (68.2%) of the STATs and 264 (23.9%) of the ALERTs(1). Operative intervention was required in 2118 patients (47%). The overall mortality rate was 1.9%, and this increased to 5.8% in the TA group(1). There were 48 deaths (22.7%) in the STAT group, 29 deaths (2.6%) in the ALERT group, and 9 deaths (0.28%) in patients with no TA(1). When emergency department deaths were excluded, the remaining 60 deaths resulted in a mortality rate of 1.3%. CONCLUSIONS Our Level I pediatric trauma center manages a large volume of patients with significant acuity and, evidenced by a TA in 29% of the patients, a severe or very severe ISS in 16% of the patients, 16% of the patients requiring ICU admission, and 47% requiring operative intervention. The TA patients had markedly higher rates of ICU admission, ISS, and mortality. Deaths in the study were lower by almost an order of magnitude comparing TA STATs with TA ALERTs and TA ALERT patients with patients without TA. The TA criteria are in many ways very helpful and is integral to a Level I trauma center. However, opportunities were identified for improvement because of areas of "overutilization" and discordance between TA and ISS.