Massive hemorrhage is a major cause of potentially preventable death following trauma. A common consequence of hemorrhagic shock is uncontrollable bleeding from coagulopathy, leading to death from exsanguination. Even when bleeding is controlled, patients are at increased risk of complications and mortality. Reconstituted whole blood, or component therapy with packed red blood cells (PRBCs), plasma, and platelets was introduced by the military in recent conflicts in Iraq and Afghanistan with remarkable results and has been adopted by most civilian trauma centers. Despite improving coagulopathy, it is apparent that transfusion of blood components is not equivalent to whole blood transfusion. Transfusion of high plasma volumes may be associated with increased risk of allergic reaction, transfusion associated acute lung injury (TRALI), hypervolemic cardiac failure, and acute respiratory distress syndrome (ARDS). Military services have recently reintroduced fresh whole blood (WB) for standard resuscitation of massive hemorrhage, have found that WB offers a survival advantage over component therapy, and that risks of transfusion reactions are similar for WB and PRBCs. On the civilian side, whole blood is an FDA-licensed product that has been in use in pediatric open heart surgery and autologous blood donation but is no longer commonly available for other indications. However, the military results are renewing interest in whole blood for trauma resuscitation. The use of low-antibody titer whole blood leukoreduced with a platelet-sparing filter was recently approved by the University of California Los Angeles Blood and Blood Derivatives Committee and two other trauma centers for male trauma patients. This study will test the feasibility of providing stored WB for resuscitation of patients in hemorrhagic shock and determine the effects of WB on clinical outcomes as well as the effects on coagulation, fibrinolysis, and inflammation, compared to standard blood component therapy.