This project was designed to examine the epidemiology of traumatic brain injury (TBI) in Taiwan. A total of 58,563 cases of TBI was collected from 114 hospitals in Taiwan during the period July 1, 1988-June 30, 1994. Traffic accident was the major cause of TBI (69.4%), followed by falls and assaults. Motorcyclists accounted for the vast majority of TBI cases among traffic accident victims (64.5%). The Glasgow Coma Scale was used in assessing the severity. 41,646 cases (79.5%) were considered mild, 4,637 cases (8.9%) moderate, and 6,078 cases (11.6%) severe. Skull x-ray showed fracture in 7,663 cases (14.6%). Intracranial hemorrhage was identified in 28.6% of patients receiving CT scanning. Craniotomy was performed in 5,226 cases (9%). The outcome of TBI was determined by the Glasgow Outcome Scale. Death occurred in 2,621 cases (5.4%), vegetative state in 429 cases (0.9%), severe disability in 1,293 cases (2.6%), moderate disability in 1,890 cases (3.9%), and good recovery in 42,596 cases (87.2%). The severity and outcome were worse than those of Western reports. In order to alleviate this problem, a helmet use persuasion program was conducted by the Police Department in Taipei City from January to June, 1994. Results of this program showed a significant reduction of TBI-related hospitalization, severity and fatality during this period of intervention. This study points out the seriousness of TBI in Taiwan and suggests some approaches and priorities for prevention.