Objective: To assess health-related quality of life in individuals with severe traumatic brain injury at 12 months postinjury, applying the Quality of Life after Brain Injury (QO-LIBRI) instrument, and to study the relationship between injury-related factors, post-injury functioning and healthrelated quality of life. Design/subjects: The study is part of a prospective, Norwegian multicentre study of adults (≥ 16 years old) with severe traumatic brain injury, as defined by a Glasgow Coma Scale score of 3-8 during the first 24 h post-injury. A total of 126 patients were included. Methods: Socio-demographic data and injury severity variables were collected. Functioning at 3 and 12 months was assessed with the Glasgow Outcome Scale Extended (GOSE), the Functional Independence Measure (FIM), the Rivermead Post-concussion Questionnaire (RPQ), and the Hospital Anxiety and Depression Scale (HADS). Hierarchical regression analysis was applied.