Traumatic brain injury (TBI) is a public health problem with high mortality and socioeconomic repercussions. We aimed to investigate the influence of TBI severity on the length of mechanical ventilation (MV) stay and length of hospital stay and on the prevalence of tracheostomy, pneumonia, neurosurgery and death. This retrospective, observational study evaluated medical records of 67 patients with TBI admitted to Irmandade da Santa Casa de Misericórdia de São Paulo. Severity was determined according to the Glasgow Coma Scale (GCS): mild (13-15 points; 36 patients; 53.7%), moderate (9-12 points; 14 patients; 20.9%) or severe (3-8 points; 17 patients; 25.4%). Severe TBI patients had higher prevalence of tracheostomy, pneumonia and neurosurgery. No significant differences were observed between TBI severity, mortality and length of MV stay. However, TBI severity influenced the length of hospital stay. TBI severity at admission, evaluated according to the GCS, influenced the prevalence of tracheostomy, pneumonia, neurosurgery and was associated to prolonged hospital stay.