BACKGROUND: Knowledge of the factors associated with the decision to withdraw or withhold life support (WWLS) in brain-injured patients is limited. However, most deaths in these patients may involve such a decision. OBJECTIVES: To identify factors associated with the decision to WWLS in brain-injured patients requiring mechanical ventilation who survive the first 24 h in the ICU, and to analyse the outcomes and time to death. DESIGN: A retrospective observational multicentre study. SETTINGS: Twenty French ICUs in 18 university hospitals. PATIENTS: A total of 793 mechanically ventilated brain-injured adult patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Decision to WWLS within 3 months of ICU admission, and death or Glasgow Outcome Sca...