Introduction: Cerebral Edema is a condition that often occurs in patients with traumatic brain injury including traumatic mild and moderate brain injury. The improvement of serum S100B levels is later found to be related to cerebral edema volume expansion. Methods: The prospective cross-sectional study involved patients with mild and moderate traumatic brain injury (based on the Glasgow Coma Scale (GCS)). Serum S100B protein levels were analyzed using the enzyme immunoassay technique. The relationship between serum S100B serum levels and cerebral edema volume expansion will be analyzed using the chi-square test. Results: A total of 24 patients involved in the research consist of 20 male patients (83.3 %) and 4 female patients (16.7%). The average S100B levels in patients are 0.07 07 __ampersandsignplusmn; 0.14 __ampersandsignmicro;g/L, and the average volume of cerebral edema is 16.6 __ampersandsignplusmn; 23.1 __ampersandsignmicro;g/L. There is no significant correlation of the level of serum S100B to the cerebral edema volume expansion (P = 0.45). Conclusion: The level of Serum S100B does not correlate to the cerebral edema volume expansion for patients with traumatic mild and moderate brain injury.