Purpose Radiology has lagged behind other disciplines in using medicolegal data to improve patient safety. The aim of this study was to characterize a sample of closed claims files to inform radiology practice and identify opportunities for system change. Methods A retrospective analysis of 443 medicolegal closed claims provided to the Radiology Events Register. Data were provided by 2 medical defense organizations that provide medical indemnity insurance to Australian private practitioners. We calculated a procedural risk ratio (prevalence in the closed claims dataset divided by prevalence among all diagnostic imaging procedures reimbursed by the Australian Government over the corresponding timeframe) for each modality (CT, ultrasound, radiography, MRI, nuclear medicine) and some procedures. For each closed claim, the incident type was determined, and a classification of 12 patient safety fields was conducted. Results Misdiagnosis (delay or failure to correctly read imaging) accounted for 62 of error types. Modalities and procedures at higher risk of leading to a claim were: mammography (risk ratio [RR] = 4.0, 95 CI 2.9-5.5); breast ultrasound (RR = 2.8, 95 CI 1.7-4.7); total MRI (RR = 3.4, 95 CI 2.0-5.6); total CT (RR = 1.9, 95 CI 1.5-2.5), and obstetrics and gynecology ultrasound (RR = 1.9, 95 CI 1.4-2.4). Lower-risk modalities and procedures were: cardiac ultrasound (RR = 0.1, 95 CI 0.0-0.8); radiography extremities (RR = 0.7, 95 CI 0.5-0.9); and total radiography (RR = 0.8, 95 CI 0.7-0.9). Information to inform patient safety classification was limited, with a mean of 5.8 ? 1.8 (SD) fields available. Conclusions Despite its limitations, medicolegal data deserve further attention from patient safety analysts. ? 2015 American College of Radiology.