Pseudoaneurysms of abdominal aorta after blunt injury are uncommon. These events may present months and even many years after an injury. Such a pseudoaneurysm may rupture at any time which is a life threatening condition. We reported a case of a 33 years old man with a ruptured abdominal aorta pseudoaneurysm which had formed two months earlier following an automobile accident. Just after the accident the patients had admitted to the hospital. Computed tomography (CT) had revealed fractures of T9, L3 vertebral body and C6 vertebral fascet. Posterior transpedicular rod stabilization had been performed for T9 vertebral body fracture. After the operation, he had been started heparin therapy for paraplegia and immobilization. Neither CT nor abdominal USG had showed any sign of retroperitoneal hematoma or extravasations. Two months after the initial surgery, the patient was consulted to us because of his increasing abdominal pain, tenderness, sudden hemoglobin reduction and hemodynamic instability. CT of the abdomen and pelvis showed a large infrarenal aortic pseudoaneurysm. Because of the presence of huge retroperitoneal hematoma and abdominal compression signs, a surgical management was decided to be performed. The pseudoaneurysm was resected, the aortic defect was repaired with a Dacron patch, and the organized hematomas were evacuated. In such patients, even in the late period after trauma, a sudden onset of symptoms like abdominal pain, distention and hemodynamic instability should be carefully evaluated and pseudoaneurysm should be suspected.