Diagnostic peritoneal lavage has widely been replaced by emergency sonography in the evaluation of blunt abdominal trauma. CT is generally performed in cases without major hemodynamic instability in order to define non-operative treatment of injuries of the parenchymatous organs or to precise the extension of retroperitoneal, spinal and pelvic lesions. Despite the good results of this method for the mentioned indications, the low sensitivity of CT for lesions of hollow viscus should not be forgotten. We report 3 cases of lesions of the small bowel (2 perforations and 1 mesenteric lesion with ischemic bowel wall) which were not visible, even retrospectively, at the CT. Despite discrete clinical signs, these lesions were only diagnosed at the stage of obvious secondary peritonitis. These cases should remind us the limits of CT in the evaluation of abdominal visceral lesions in blunt trauma.