Abstract Background Optimal management of severe trauma patients with active hemorrhage relies on adequate initial resuscitation. Early administration of coagulation factors improves post-traumatic coagulation disorders, and four-factor prothrombin complex concentrate (PCC) might be useful in this context. Our main hypothesis is that four-factor PCC in addition to a massive transfusion protocol decreases blood product consumption at day 1 in severe trauma patients with major bleeding. Methods This is a prospective, randomized, multicenter, double-blind, parallel, controlled superiority trial. Eligible patients are trauma patients with major bleeding admitted to a French level-I trauma center. Patients randomized in the treatment arm receive 1 mL/kg (25 IU/ml of Factor IX/Kg) four-factor PCC within 1-h post-admission while patients randomized in the controlled group receive 1 mL/kg of saline solution 0.9% as a placebo. Treatments are given as soon as possible using syringe pumps (120 mL/h). The primary endpoint is the amount of blood products transfused in the first 24 h post-admission (including red blood cells, frozen fresh plasma, and platelets). The secondary endpoints are the amount of each blood product transfused in the first 24 h, time to achieve prothrombin time ratio < 1.5, time to hemostasis, number of thrombo-embolic events at 28 days, mortality at 24 h and 28 days, number of intensive care unit-free days, number of ventilator-free days, number of hospital-free days within the first 28 days, hospitalization status at day 28, Glasgow outcome scale extended for patients with brain lesions on initial cerebral imaging, and cost of each strategy at days 8 and 28. Inclusions have started in December 2017 and are expected to be complete by June 2021. Discussion If PCC reduces total blood consumption at day 1 after severe trauma, this therapy, in adjunction to a classic massive transfusion protocol, may be used empirically on admission in patients at risk of massive transfusion to enhance coagulation. Moreover, this treatment may decrease blood product-related complications and may improve clinical outcomes after post-traumatic hemorrhage. Trial registration ClinicalTrials.gov NCT03218722 . Registered on July 14, 2017