Background: The resuscitation of trauma patients with critical bleeding may follow a formulaic approach using high ratios of blood components or a viscoelastic haemostatic assay (VHA) guided approach. The aim of this study was to compare the two strategies for resuscitation of shocked trauma patients. Methods: This was a registry-based cohort study including shocked trauma patients from two trauma centres–one practising a formulaic approach, with VHA unavailable during trauma resuscitation and the other practicing a VHA-guided resuscitation strategy. The primary outcome was the total units of blood components transfused in 24 h after adjusting for differences in baseline characteristics and time to death. Results: Between 01 Jan 2020 and 31 Dec 2022, 152 eligible patients were categorised to the formulaic group and 40 to the VHA group. Prehospital times were longer in the formulaic group (2.0 vs. 1.4 h), and more patients in the VHA group (38% vs. 17%) were transfused prehospital blood components. Formulaic resuscitation was associated with significantly more blood components transfused (adjusted incidence rate ratio 1.5; 95%CI: 1.4–1.7, p < 0.001). Using a formulaic approach, patients were administered more red blood cells, plasma and platelets, but fewer cryoprecipitate. There was no significant association of the formulaic approach with in-hospital mortality (adjusted odds ratio 2.4; 95%CI: 0.7–8.0, p = 0.17). Conclusions: Given the cost and potential adverse effects of blood component transfusions, VHA-guided transfusion strategies present an attractive option, particularly among centres managing high volumes of shocked patients. Further trials, enrolling the population most likely to benefit from precision transfusion strategies, are indicated.