Penetrating cardiac injury is a highly mortal condition, with overall mortality rates approaching 90%. However, survival rates can be dramatically improved with timely operative intervention. Prompt resuscitative thoracotomy in selected patients can achieve overall survival rates exceeding 50%. Therefore, the effective provision of resuscitative thoracotomy should be considered in all trauma systems, which deliver care for penetrating trauma. This chapter describes the epidemiology of penetrating cardiac injury, the factors associated with survival, and reviews current guidelines governing clinical practice. The technique for resuscitative thoracotomy is described, along with a discussion of the reception and management of patients undergoing this procedure. Notably, while the majority of emergency department and pre-hospital resuscitative thoracotomies are performed by non-surgeons, it is important for surgeons to understand the circumstances and techniques used by non-surgeons to perform the technique to optimise patient outcomes following admission. Resuscitative thoracotomy also has a role in managing traumatic cardiac arrest not associated with cardiac injury. This is summarised, but is not the main focus of the chapter.