Primary objective: To identify correlates of aggressive behaviours in patients with acquired brain injury (ABI). Methods and procedures: During a 16 month period, patients who had ABI and who had been aggressive during hospitalization (n?=?32) were identified by hospital staff. A comprehensive chart review of these patients was completed. Results were compared against results of a matched patient sample who had not been aggressive (32). Main outcomes and results: Five variables which were significantly correlated with aggression were entered into a standard logistic regression. The model explained 61.4% of the total variance and successfully predicted 87.5% of the non-aggressive group and 78.1% of the aggressive group. The overall correct prediction rate was 82.8%. Of the five variables, four were found to significantly contribute to the predictive ability of the model: An education of 10 years or less, a history of aggression, dependence on staff for assistance with activities of daily living and a hospitalization period of 51 days or more. Conclusions: The results highlight some variables related to aggression by patients with ABI in the hospital environment and can be utilized in staff education and training programmes to increase the awareness of risk factors.