Objective To evaluate the reliability and validity of total Glasgow Coma Scale （GCSt） versus the motor component （GCSm） alone for the emergency department assessment of traumatic injuries.Methods A total of 261 trauma patients with GCSt≤13 and GCSm≤5 were selected for the study.GCS scores of the patients were assessed independently by trained resuscitation nurses and triage nurses, and the inter-rater reliability was compared.Validity was determined by comparing the predictive value of the GCSm and GCSt for Injury Severity Score (ISS)≥16 and death in the emergency department.Results The inter-rater reliability (ICC) for GCSm and GCSt was 0.948 and 0.986, respectively.Bland-Altman analysis showed that both instruments had more than 95% of the points within the 95% limit of agreement.For predicting ISS≥16 points, the sensitivity for GCSm and GCSt was 75.56% and 68.86%, the specificity was 71.30% and 79.17%, and the AUC was 0.763 and 0.773, respectively （both P＞0.05）.For predicting death in the emergency department, the sensitivity for GCSm and GCSt was equal at 70.00%, the specificity was 65.98% and 74.27%, and the AUC was 0.689 and 0.703, respectively （both P＞0.05）.Conclusion For trauma victims, the GCSm and GCSt show good inter-rater agreement among trained emergency nurses, and GCSm is equivalent to or more sensitive than the full GCS.In view of its simplicity the motor component of the GCS should replace the GCS in assessment of traumatic injuries.