Traumatic aneurysm of both the thoracic aorta and the left ventricle are extremely rare in children because it is characterized by high mortality. We report a case which we experienced recently with sucessful outcome. A Five-year-old boy had a blunt trauma by bongo bus. He had pulmonary hemorrage and pericardial effusion complicated by multiorgan failure threatening his life. Aneurysm of LV and Descending aorta were showed by 2-D echocardiogram and MRI. The atient underwent successful corrective surgery 2 and half momths after trauma, the Postoperative status of this patient was uneventful, now he is being followed up the OPD.