IN AN ATTEMPT to evaluate the response of patients who have low admission Glasgow Coma Scale scores (GCS) after a penetrating craniocerebral injury to aggressive management, we evaluated a series of 190 patients with penetrating injuries who presented with a GCS score of 3, 4, or 5 during a 6-year period. Entrance criteria required replicable neurological examinations that were not altered by the presence of hypotension, drugs/toxins, or systemic injury. The surgical patients included 21 patients with an admission GCS score of 3, 24 with an admission GCS score of 4, and 15 with an admission GCS score of 5. All patients underwent surgical intervention and aggressive perioperative management in the neurosurgical intensive care, including resuscitative protocols. Five of the patients with a GCS score of 3 survived, all with poor outcomes. Seven of the patients with a GCS score of 4 survived, although only one had a good outcome. Eleven of the patients with a GCS score of 5 survived. Five had a Glasgow Outcome Score of 2, five had a Glasgow Outcome Score of 3, and one had a Glasgow Outcome Score of 4. We have devised a prospective model of outcome based on our series in an attempt to predict nonsurvivors at admission (while overpredicting for survivors). The variables most predictive of mortality include admission GCS score and subarachnoid hemorrhage in one model and admission GCS score and pupillary changes in a second, when pupillary response was definitive at admission (P≤ 0.00005). Important variables most predictive of morbidity include admission GCS score, bihemispheric injury when associated with intraventricular hemorrhage, and diffuse fragmentation (P< 0.001). It should be noted that disseminated intravascular coagulation was not included in our model. Disseminated intravascular coagulation was always associated with poor outcome when present in any traumatic injury. In considering outcome, we conclude that patients with admission GCS scores of 3, 4, or 5 are not likely to benefit (have a good outcome) from surgical intervention. Patients presenting with admission GCS scores of 3, 4, or 5 without radiological evidence of subarachnoid hemorrhage, ventricular involvement, or fragmentation in the presence of reactive pupils potentially should be followed more closely. We will continue to expand our series to define those prognostic variables that suggest good outcome in patients with GCS scores of 5 or higher.