The goal of this study was to investigate the outcomes of patients with traumatic brain injury (TBI) who had Glasgow Coma Scale (GCS) scores of 3 or 4, and were aged 66 years or older. Between January 2001 and December 2005, 13 European centers enrolled patients with severe brain trauma. Data sets of all patients who had a GCS score of 3 or 4 and were 66 years of age or older were analyzed. Outcomes were classified according to the Glasgow Outcome Scale (GOS) 12 months post-trauma as "favorable" (GOS score of 4 or 5), or "unfavorable" (GOS score of 1-3); relevant data for patients of the two groups were compared. Variables were analyzed by univariate analyses (chi-square, Wilcoxon-Mann-Whitney, and Fisher's exact tests), and a p value of <0.05 was considered significant. We analyzed 100 patients identified from the database as having GCS scores of 3 or 4 and age over 65 years. Factors having significant effects on outcomes were worse results of the Injury Severity Score (ISS), Trauma and Injury Severity Score (TRISS), and Abbreviated Injury Scale (AIS) for the head. Closed or partially closed basal cisterns and/or midline shift >15 mm were also associated with unfavorable outcomes, as was subarachnoid hemorrhage (SAH). Patients with GCS scores of 3 or 4 who are older than 65 years have a poor, but not hopeless, prognosis. Confirmed factors predicting poor prognosis for this group of patients were closed basal cisterns and midline shift >15 mm on the first CT scan. Factors possibly related to favorable outcomes were female gender, lower trauma severity, open or partially open basal cisterns, and no midline shift on the first CT scan.