During the past decade, the nonoperative management of children with blunt abdominal trauma without operation has improved dramatically by virtue of the development of medical technology. However, missed injuries or complications after nonoperative management often are associated with serious morbidity. The authors evaluated 86 patients between 1990 and 1994 who had intraabdominal solid-organ injury (excluding retroperitoneal organs) owing to blunt trauma. The liver was injured in 43 cases, the spleen in 36, and the pancreas in 14. Initially, 68 patients (79%) were managed conservatively and 18 underwent surgery because of unstable vital signs or associated injuries. Three patients had delayed surgery more than 48 hours after trauma) because of initially missed injuries (complete infarction of the spleen, duodenal injury, major pancreatic injury). Eleven patients (17%) with nonoperative management had a total of 13 complications. The most common complications were pleural effusion and atelectasis. One patient had prolonged ileus owing to delayed absorption of an intraperitoneal hematoma, and the symptom was relieved by aspiration of the hematoma. A huge hepatic subcapsular hematoma developed in another patient and required percutaneous drainage with a pigtail catheter for 5 weeks. A pancreatic pseudocyst detected on the 16th hospital day also was drained with a pigtail catheter. A splenic abscess developed in another patient 24 days after a splenic injury, which was treated with ultrasound-guided aspiration. No patients died as a result of nonoperative management. In conclusion, even though patients with blunt abdominal trauma are stabilized and nonoperative management decided on, careful follow-up for a prolonged period is still necessary to prevent missed injuries or late complications.