Patients can provide a unique perspective on the safety of care in hospitals. Understanding that the extent to which the way hospitals are organized for quality and safety is associated with patient perceptions of care is becoming increasingly valued and necessary for the direction of targeted interventions across healthcare systems. The UK-developed patient measure of safety (PMOS) assesses eight domains of ward safety from the patient point of view and has recently been adapted and piloted in Australia. The aim of this study is to test the psychometric properties of PMOS-Australia (PMOS-A) amongst a large cohort of hospitalized patients.