Objective To evaluate the interobserver reliability of a new scale created for quantitatively assessing brain swelling in traumatic brain injury (TBI) patients using the computed tomography (CT) findings in three levels. Methods Computed tomography scans of severe head injury patients were randomly selected from a tertiary hospital image database and evaluated by independent groups of neurosurgeons, neurosurgery residents, radiologists, and intensivists from the same hospital. Each specialist assessed the tomographic findings, applying zero to six points in a new scale. The Kappa coefficient was calculated to assess interobserver agreement. Results The highest reliability coefficient was obtained by the neurosurgeons group (0.791; 95% confidence interval [CI]: 0.975–0.607; p < 0.001), followed by the neurosurgery residents group (0.402; 95%CI: 0.569–0.236; p < 0.001) and by the radiologists group (0.301; 95%CI: 0.488–0.113; p < 0.002). The lowest coefficient was found among the intensivists (0.248; 95%CI: 0.415–0.081; p ¼ 0.004). Conclusion The proposed scale showed good reliability among neurosurgeons, and moderate overall reliability. This tomographic classification might be useful to better assist severe TBI victims, allowing to identify the worsening or amelioration of brain swelling, which should be further investigated. The scale seems to be feasible, even in low income countries,where the costof intracranial pressure (ICP)monitoring is higher than thatofCTs.