PURPOSE To evaluate the diagnostic value of ultrasonography (US) in detecting intraabdominal injuries in patients with blunt abdominal trauma. MATERIALS AND METHODS Blunt trauma patients admitted to the emergency department from January 2002 to August 2003 were retrospectively evaluated. A total of 454 patients with blunt abdominal trauma who underwent US examination were included. Ultrasonography results were compared with findings of CT, diagnostic peritoneal lavage, laparotomy and clinical course. Sensitivity, specificity, positive and negative predictive values of US in detecting free fluid, intraabdominal parenchymal organ injury or both were calculated.RESULTS Computed tomography, diagnostic peritoneal lavage and laparotomy results showed that intraabdominal organ injury was present in 37 of 454 patients. Ultrasonography examinations were positive in 51 patients. True-positive findings were seen in 32 of these patients. In these 32 patients, US examination showed free fluid in 19, fluid and abdominal organ injury in 11 and only abdominal organ injury in 2. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of US in detecting intraabdominal injury were 86.5%, 95.4%, 62.7%, 98.7% and 94.7%, respectively.CONCLUSION Ultrasonography has high diagnostic performance in the screening of patients with blunt abdominal trauma. Abdominal US is a useful and valuable diagnostic tool after clinical evaluation in patients with blunt abdominal trauma. Because of its high negative predictive value, we recommend that clinical follow up is adequate for patients whose US results are negative for intraabdomial organ injury.