Objective: The use of scoring systems to evaluate severity of illness in ICU trauma patients provides prediction of more reliable prognosis. The aim of this study was to retrospectively evaluate the value of revised trauma score (RTS) and trauma and injury severity score (TRISS) in addition to APACHE II and Glasgow coma score (GCS) in the prediction of mechanical ventilation and prognosis in ICU trauma patients. Material and Methods: In this study, 349 trauma patients were examined. Patients were rated in terms of age, gender, etiology of trauma, clinic diagnoses, requirement for mechanic ventilation, duration of mechanic ventilation, and intensive care unit stay, mortality rates, GCS, APACHE II, RTS, and TRISS soring systems. Results: Median scores of APACHE II, GCS, RTS and TRISS were 13, 9, 6, and 10.8, respectively. When APACHE II and TRISS increased and GCS and RTS decreased, mechanical ventilation requirement and mortality increased. Logistic regression analysis revealed that high TRISS, older age and low RTS were strongly correlated with mortality. Conclusion: Using different scoring systems such as RTS and TRISS allows better prediction of the mechanical ventilation requirement and prognosis, and when used with APACHE II and GCS scoring systems with established reliability will contribute to the triage, monitorization and management of patients in ICU.