The Glasgow Coma Scale (GCS) was first introduced in the 1970s to provide a simple and reliable method of recording and monitoring change in the level of consciousness of head injured patients. Since its introduction, the GCS has been widely utilized in the trauma community and its use expanded beyond the original intentions of the score. In the context of traumatic injury, this paper discusses the use of the GCS as a predictor of outcome, the limitations of the GCS, the reliability of the GCS and potential alternatives through a critical review of the literature. The relevance to Australian trauma populations is also addressed.