PURPOSE: The field trauma triage for injured patients is essential for trauma care system. In this study, agreement of patient evaluation between by prehospital EMS personnel and by hospital staffs and the appropriateness of prehospital triage were evaluated. METHODS: This observational study was conducted from September to October 2012 for 5 weeks. During this period, EMT evaluated patient's severity according to guideline for field triage and recorded. Same guideline was applied in 26 hospitals for patients with EMS use. Kappa statistics were used to measure agreement for each item of guideline. Finally, over-triage and under-triage rate of EMT were calculated. RESULTS: During study period, total 3,106 patients were transferred to 26 hospital emergency departments with EMS use. Kappa statistics for "vital signs" items were 0.45 for mentality lower than V and 0.44 for systolic blood pressure lower than 90 mmHg as a moderate agreement. In "anatomy of injury" items Kappa statistics were very low. In "mechanism of injury" items Kappa statistics were 0.28 for high-rise fall down and 0.27 for high energy traffic accident but in other items Kappa statistics were very low. 362 patients (12.0%) were over-triaged and 281 patients (9.3%) were under-triaged. CONCLUSION: Field triage can be applied but need to evaluate and modify in order to become accurate and sensitive for decision of transportation.