OBJECTIVE: The aim of this study was to examine the predictive validity of unstructured clinical risk assessment and associated risk factors for aggression in predicting physical aggression in children admitted to an Australian psychiatric inpatient facility. METHOD: A retrospective review of patient records was conducted at the State Wide Child Inpatient Unit during late 2009 for the period September 2006-July 2009. Children between the ages of 8 and 13 were included in analyses. Information collected included admission risk assessment ratings, critical incident reports, patient diagnoses and history of aggression and trauma. RESULTS: A total of 127 children (aged 8-13 years) were included in retrospective analyses. Higher aggression risk rankings were predictive of the frequency but not the severity of aggression. A diagnosis of a disruptive behaviour disorder and a history of being a victim of trauma were also predictive of engagement in aggression; however, were not as predictive as the risk assessment. A high risk assessment rating for aggression was better able to predict engagement in aggressive behaviour than a history of physical aggression alone. CONCLUSIONS: Based on professional expertise, prior experience and intuition, clinicians were able to successfully predict engagement in aggressive behaviour during patient admission to a child psychiatric inpatient units.