Objective: To report trauma outcome from a developing country based on the Trauma and Injury Severity Scoring (TRISS) method and compare the outcome with the registry data from Major Trauma Outcome Study (MTOS). Design: Registry based audit of all trauma patients over two years. Setting: Emergency room of a teaching university hospital. Subjects: 279 injured patients meeting trauma team activation criteria including all deaths in the emergency room. Outcome measures: TRISS methodology to compare expected and observed outcome. Statistical analysis: W, M, and Z statistics and comparison with MTOS data. Results: 279 patients meeting the trauma triage criteria presented to the emergency room, 235 (84.2%) were men and 44 (15.8%) women. Blunt injury accounted for 204 (73.1%) and penetrating for 75 (26.9%) patients. Seventy two patients had injury severity score of more than 15. Only 18 (6.4%) patients were transported in an ambulance. A total of 142 (50.9%) patients were transferred from other hospitals with a mean prehospital delay of 7.1 hours. M statistic of our study subset was 0.97, indicating a good match between our patients and MTOS cohort. There were 18 deaths with only one unexpected survivor. The expected number of deaths based on MTOS dataset should have been 12. Conclusions: Present injury severity instruments using MTOS coefficients do not accurately correlate with observed survival rates in a developing country.