Background/Purpose: The isolated finding of free intraperitoneal fluid on abdominal computed tomography (CT) scan after blunt trauma in adults is considered an indication for laparotomy by many trauma surgeons. The authors wished to determine if these guidelines are applicable to children. Methods: A retrospective chart review was conducted. The authors included all children (≤ 12 years of age) sustaining blunt abdominal trauma who were admitted to our institution between January 1, 1994 and November 1, 1998. Results: There were 814 children admitted, and 437 had abdominal CT scans. Thirty-four studies showed free fluid associated with solid organ injuries, spine or pelvic fractures, or pneumoperitoneum, and were excluded. Thirty-two children had free fluid without associated injuries and formed the basis for the study. Five of these children underwent laparotomy based on the CT finding alone. The remaining 27 were observed with serial abdominal examinations and did not require surgical intervention. Only 1 of the 5 children who underwent surgery for the finding of isolated free fluid had a therapeutic laparotomy. In comparison, during the same period, 38 children underwent laparotomy after blunt injury based only on physical examination findings with a therapeutic laparotomy rate of 68%. The therapeutic laparotomy rate was significantly higher when the procedure was based solely on clinical examination as compared with the isolated finding or free fluid on the abdominal CT (26 of 38 v 1 of 5, P < .05). Conclusion: In contrast to adults, finding isolated free fluid on abdominal CT scans in children after blunt trauma does not dictate immediate surgical exploration. Copyright (C) 2000 by W.B. Saunders Company.