PURPOSE: To evaluate the differences of associated factors in thoracolumbar fractures according to the mechanism of injury, level and type of the fracture, associated injuries were investigated for comparison between injuries by fall from height and by in-car accident injury. MATERIALS AND METHODS: Medical records and X-ray findings of 249 patients with fractures of thoracolumbar spine were reviewed retrospectively. Among them, 169 patients were injured by the two main causes. McAfee classification was adopted to determine the type of fracture. Associated injuries were classified as head and neck, chest and abdomen, pelvis, proximal and distal extremity, and neurologic deficit. Statistical analysis using Chi-square method was used for comparison between the two groups. RESULTS: In overall patients, the most common cause of thoracolumbar fracture was fall from height (44.6%) followed by in-car accident (23.3%) and fall down (16.9%). In fall-from height gruoup, burst fracture was the most common (44.1%) while flexion-distraction injury was the most popular (39.7%) in in-car accident group (p=0.05). Comparison according to height of fall showed significant increase of multiple fractures (p=0.0326). Associated injuries of distal lower and upper extremities and pelvis were common in fall-from-height group, while injuries of head and neck, proximal part of upper extremity, chest and abdomen were common in in-car accident patients. CONCLUSION: Type of fracture and distribution of associated injuries were significantly different between the two main causes of thoracolumbar injury, which seemed to be useful for understanding the mechanical events of injury and detecting associated injuries in each victim.