Aim: To determine the predictive significance of the Rotterdam score in evaluating the functional prognosis of severe traumatic brain injuries. Material and Methods: This retrospective study was conducted at our hospital, focusing on adult patients with severe traumatic brain injury (TBI) admitted to the hospital. The study population consisted of 90 adult aged 18-40 years who were admitted with severe TBI and had undergone brain computed tomography (CT) scans during their hospitalization. The inclusion criteria for this study were as follows: adult aged between 18 and 40 years, admission with a diagnosis of severe TBI as indicated by a Glasgow Coma Scale (GCS) score of 8 or less, and the availability of complete medical records and brain CT scans. Results: The presence of cisterns was observed in 45 patients (50%), and 45 patients (50%) had compressed or absent cisterns. Midline shift of more than 5 mm was noted in 25 patients (27.78%), while 65 patients (72.22%) had no or minimal midline shift. Epidural mass lesions were present in 20 patients (22.22%) and absent in 70 patients (77.78%). Intraventricular hemorrhage or subarachnoid hemorrhage was observed in 10 patients (11.11%), while 80 patients (88.89%) did not exhibit these conditions. Scores were distributed as follows: Score 1 (11.11%), Score 2 (22.22%), Score 3 (16.67%), Score 4 (22.22%), Score 5 (16.67%), and Score 6 (11.11%). Higher scores indicate more severe brain injury based on the Rotterdam scoring system. The functional outcomes at 6 months post-injury were assessed using the Glasgow Outcome Scale (GOS). The distribution of outcomes was as follows: 22.22% of patients had died (GOS 1), 11.11% were in a vegetative state (GOS 2), 27.78% had severe disability (GOS 3), 22.22% had moderate disability (GOS 4), and 16.67% had a good recovery (GOS 5). Conclusion: This study highlights the prognostic value of the Rotterdam CT scoring system in adult patients with severe traumatic brain injury (TBI). Higher Rotterdam scores were significantly associated with poorer functional outcomes, as assessed by the Glasgow Outcome Scale (GOS). The strong predictive capability of the Rotterdam score, with an area under the curve (AUC) of 0.78, supports its utility in clinical practice for early assessment and management of severe adult TBI.