Elevated serum neuron-specific enolase levels are correlated with brain cell damage. Low scores according to Glasgow Coma Scale are also considered as serious poor prognostic factor. The aims of the study were to investigate whether there is a correlation between the two measurements in patients with traumatic brain injury and whether serum neuron-specific enolase levels have potential as a screening test to predict outcome. A total of 169 consecutive patients with traumatic brain injury admitted to our clinic between 2002 and 2005 are included in this study. Those patients, who had any major health problem before trauma, were excluded from the study. However, patients with isolated head injury were included in the study. Serial serum neuron-specific enolase concentrations taken at the first 2, 24, and 48 h after traumatic brain injury were analyzed. A computed tomography was performed on each patient on admission. Their Glasgow Coma Scale scores were recorded serially. The relationship between Glasgow Coma Scale scores and the serum neuron-specific enolase levels were assessed by statistical methods. There was a significant negative correlation between the serum neuron-specific enolase levels and Glasgow Coma Scale scores. The levels of neuron-specific enolase were significantly higher in the patients who died in 30 days after trauma and whose scores were lower than or equal to 8 points in Glasgow Coma Scale. Although there are several serious limitations of the use of neuron-specific enolase as a biomarker in traumatic brain injury (i.e., hypoperfusion, extracranial trauma, bleeding, liver, or kidney damage also increase the level of neuron-specific enolase), its concentrations may be useful as a practical and helpful screening test to identify neurotrauma patients who are at increased risk and may provide supplementary estimation with radiological and clinical findings.