Recent clinical reviews have helped to clarify the role of Emergency Department (E.D.) thoracotomy in critically injured adults. However, guidelines in the pediatric population remain ill defined. The purpose of this report is to examine the yield of E.D. thoracotomy in patients ≤ 18 years of age to allow for a more cost-effective application of this heroic measure. From an 11-year experience of 689 consecutive E.D. thoracotomies, 83 patients (12%) were ≤ 18 years old. Mechanism of injury was blunt trauma in 57%, gunshot wound in 30%, and stab wound in 13%. Mean age was 15 years and 71% were male. Survival by injury mechanism was 9% (1/11) for stab wound, 4% (1/25) for gunshot wound, and 2% (1/47) for blunt trauma. Sixty-nine patients presented to the E.D. without vital signs and only one, a 16-year-old with stab wounds to the chest and abdomen, survived. In contrast, two (14%) among 14 patients presenting with vital signs were salvaged. As in adults, outcome was largely determined by injury mechanism and physiologic status on E.D. presentation. Blunt trauma, the predominant mechanism of lethal injuries in children, had a dismal outcome, with only 2% salvage and no survivors when vital signs were absent.This study demonstrates a similar outcome for E.D. thoracotomy in children compared to adults, and supports a selective policy of liberal use in penetrating injury irrespective of physiologic status but limited in those arriving lifeless following blunt trauma.