We report a 6-year-old boy with acute stress reaction and dissociative disorders, who suffered multiple injury in a traffic accident without cerebral contusion. He was still crying, suffered sleep disorders, was unable to communicate and showed hemiplegia a week after the injury. Brain CT showed no high or low attenuation areas. Cervical X-ray revealed neither fractures nor dislocation and cervical MRI showed no high or low intensities. His psychogenic symptoms improved temporarily both times 2.5mg of midazolam was intramusculary administered for CT scans and MRI. His psychogenic symptoms and hemiplegia remarkably and permanently disappeared after an intramuscular administration of 5mg of midazolam. The clinical course suggested acute stress reaction and dissociative disorders. Like adults, children may exhibit psychogenic symptoms despite the absence of cerebral contusions on CT scan and MRI, as a result of acute stress reaction following extremely frightening experiences. Focal neurological signs which are inexplicable by X-ray, CT or MRI may indicate dissociative disorders.