Blunt traumas of the abdomen and thorax are important clinical problems in pediatric ages. Severity of trauma may not always be compatible with the patients′ clinical situation. A 2-year-old male child was admitted to our emergency clinic as a result of tractor crash accident. Physical examination of the child was normal. The abdominal and thoracic ultrasonography (USG) examination performed in the emergency clinic was normal. In thoracic computed tomography (CT) scan of the patient, there was irregularity of the right diaphragmatic contour that was described as micro perforation-rupture (the free air was just in the perihepatic and retroperitoneal area, which was not passing through the abdomen). The patient was followed-up for 1 week in the hospital with a diagnosis of retroperitoneal diaphragmatic rupture. It is not appropriate to decide the severity of trauma in childhood on the basis of clinical findings. Although severe trauma and sustaining radiological examinations, the patients′ clinical pictures may be surprisingly normal, as in our patient. In such cases, there may not be any clinical symptom. CT scan examination must be preferred to USG for both primary diagnosis and follow-up of these patients. According to the current literature, there is no reported case with retroperitoneal rupture of the diaphragm.