Summary. Background: Reagent-supported thromboelastometry with the rotation thrombelastography (e.g. ROTEM®) is a whole blood assay that evaluates the visco-elastic properties during blood clot formation and clot lysis. A hemostatic monitor capable of rapid and accurate detection of clinical coagulopathy within the resuscitation room could improve management of bleeding after trauma. Objectives: The goals of this study were to establish whether ROTEM correlated with standard coagulation parameters to rapidly detect bleeding disorders and whether it can help to guide transfusion. Methods: Ninety trauma patients were included in the study. At admission, standard coagulation assays were performed and ROTEM parameters such as clot formation time (CFT) and clot amplitude (CA) were obtained at 15 min (CA15) with two activated tests (INTEM, EXTEM) and at 10 min (CA10) with a test analyzing specifically the fibrin component of coagulation (FIBTEM). Results: Trauma induced significant modifications of coagulation as assessed by standard assays and ROTEM. A significant correlation was found between prothrombin time (PT) and CA15-EXTEM (r = 0.66, P < 0.0001), between activated partial thromboplastin time and CFT-INTEM (r = 0.91, P < 0.0001), between fibrinogen level and CA10-FIBTEM (r = 0.85, P < 0.0001), and between platelet count and CA15-INTEM (r = 0.57, P < 0.0001). A cutoff value of CA15-EXTEM at 32 mm and CA10-FIBTEM at 5 mm presented a good sensitivity (87% and 91%) and specificity (100% and 85%) to detect a PT > 1.5 of control value and a fibrinogen less than 1 g L−1, respectively. Conclusions: ROTEM is a point-of-care device that rapidly detects systemic changes of in vivo coagulation in trauma patients, and it might be a helpful device in guiding transfusion.