HYPOTHESIS: A massive transfusion protocol (MTP) decreases the use of blood components, as well as turnaround times, costs, and mortality. DESIGN: Retrospective before-and-after cohort study. SETTING: Academic level I urban trauma center. Patients and METHODS: Blood component use was compared in 132 patients during a 2-year period following the implementation of an MTP; 46 patients who were treated the previous year served as historical control subjects. INTERVENTION: Introduction of an MTP that included recombinant factor VIIa for patients with exsanguinating hemorrhage. MAIN OUTCOME MEASURES: The amount of each blood component transfused, turnaround times, blood bank and hospital charges, and mortality rates. RESULTS: After introduction of the MTP, there was a significant decrease in packed red blood cells, plasma, and platelet use. The turnaround time for the first shipment was less than 10 minutes, and the time between the first and second shipments was reduced from 42 to 18 minutes, compared with historical controls. The decreased use of blood products represented a savings of $2270 per patient or an annual savings of $200, 000, despite increased costs for recombinant factor VIIa. There was no difference in mortality in either group; it remained around 50%. Thromboembolic complications did not increase, despite a significant increase in the use of recombinant factor VIIa. CONCLUSIONS: The MTP resulted in a reduction in the use of blood components with improved turnaround times and significant savings. Mortality was unaffected. The use of recombinant factor VIIa did not increase thromboembolic complications in these patients.