Context: Part-time personnel are an integral part of the Australian Army. With operational deployments increasing, it is essential that medical teams identify the patterns of injuries sustained by part-time personnel in order to mitigate the risks of injury and optimize deployability. Objective: To compare the patterns of reported work health and safety incidents and injuries in part-time and full-time Australian Army personnel. Design: Retrospective cohort study. Setting: The Australian Army. Patients or Other Participants: Australian Army Reserve and Australian regular Army populations, July 1, 2012, through June 30, 2014. Main Outcome Measure(s): Proportions of reported work health and safety incidents that resulted in injuries among Army Reserve and regular Army personnel and specifically the (a) body locations affected by incidents, (b) nature of resulting injuries, (c) injury mechanisms, and (d) activities being performed when the incidents occurred. Results: Over 2 years, 15 065 work health and safety incidents and 11 263 injuries were reported in Army Reserve and regular Army populations combined. In the Army Reserve population, 85% of reported incidents were classified as involving minor personal injuries; 4% involved a serious personal injury. In the regular Army population, 68% of reported incidents involved a minor personal injury; 5% involved a serious personal injury. Substantially lower proportions of Army reservist incidents involved sports, whereas substantially higher proportions were associated with combat training, manual handling, and patrolling when compared with regular Army incidents. Conclusions: Army reservists had a higher proportion of injuries from Army work-related activities than did regular Army soldiers. Proportions of incidents arising from combat tasks and manual handling were higher in the Army Reserve. Understanding the sources of injuries will allow the medical teams to implement injury-mitigation strategies.