Introduction: Minor head trauma is due to the transfer of a mechanical energy to the brain caused by a traumatic event. The present study was accomplished aiming to investigate the cleaved tau protein (CTP) as a brain injury biomarker among patients with minor head trauma.Patients And Methods: This observational study was performed on patients with minor head trauma in 2017 who referred to emergency department of Imam Khomeini Hospital and Golestan Hospital of Ahvaz, Iran. The patients over the age of 16 years old with minor head trauma, who had computed tomography (CT) scan at most 10 hrs after the incident, and consented to participate in the study, were enrolled. C-tau evaluation was performed by the enzyme-linked immunosorbent assay (ELISA) method with monoclonal antibodies detecting the C-tau marker. Investigation of the injury after 3 months of minor head trauma was conducted using a post-concussion syndrome questionnaire (RPCS).Results: In this study, 86 patients were evaluated. CTP was positive in 14% of the patients and the results revealed that there was a significant relationship between traumatic brain injury (TBI) and positive CTP (p < 0.0001). The CTP had a sensitivity and specificity of, respectively, 92% and 100% in detecting intracranial trauma. In addition, positive and negative predictive powers for this marker were 100% and 98%, respectively.Conclusion: In general, contrary to previous studies, the findings of this study suggest that evaluation of the CTP levels can be a strong biomarker with high sensitivity and specificity in detecting TBI.