The incidence of traumatic brain injury (TBI) has increased with the advanced technology of society. A careful evaluation of associated problems, initial severity, and complications is important for the acute management and rehabilitation of patients with TBI. To predict the rehabilitation potentials of patients with TBI, we have retrospectively investigated the causes, types of injury, associated problems, and complications in 186 patients and also assessed the rehabilitation outcomes by measuring the functional gains according to the types of brain injury and the initial severities evaluated by the Glasgow coma scale in 82 patients. The functional gains were measured by differences of the Mini-mental status examination, PULSES profile, and Barthel index of pre- and post-rehabilitation states. The incidence of TBI was highest in the 3rd decade men and the most common cause was a traffic accident (120 cases, 64.5%). The types of brain injury were a diffuse axonal injury, 87 cases (46.8%); epidural hematoma, 21 cases (11.3 %); subarachnoid hemorrhage, 25 cases (13.4%); subdural hematoma, 28 cases (15.1%); and intracerebral hematoma, 25 cases (12.9%). Common associated problems were fractures and injuries of nervous system. The 7th cranial nerve and the peroneal nerve were the most common injuries for cranial and peripheral nerves, respectively. Common complications were pulmonary and skin disorders. Total hospital stay and the duration for rehabilitation were not significantly different by the types of injury. Functional gain tended to be higher in the intracerebral hematoma compared to the other types of brain injury. The functional gain was statistically higher in patients with initial severity of moderate degree according to the Glasgow coma scale. In conclusion the moderate traumatic brain injured patients seem to have a higher potential for the good functional outcome.