Pelvic ring fractures can range from minor nondisplaced fractures in frail geriatric patients to life-threatening injuries associated with significant hemorrhage in polytrauma patients. In those patients with high-energy injuries, the treating surgeon should have a high index of suspicion for bleeding within the pelvis as well as associated injuries. The classification and initial treatment of pelvic ring fractures is based on the mechanism of injury, degree of displacement, and the overall condition of the patient. Displaced fractures and nondisplaced fractures that are unstable benefit from surgical repair. In cases of hemodynamic instability, provisional external fixation is a useful tool to achieve a temporary reduction and stabilize the patient to allow for further resuscitation. Despite advances in surgical technique and implants the open management of displaced pelvic ring fractures remains challenging and should only be performed by surgeons with specialized training. The focus of this chapter will be on the diagnosis, classification, and initial treatment of pelvic ring fractures.