Objective: To document blood component usage in the UK medical treatment facility, Afghanistan, over a period of 4 years; and to examine the relationship with transfusion capability, injury pattern and survival. Background: Haemostatic resuscitation is now firmly established in military medical practice, despite the challenges of providing such therapy in austere settings. Materials and Methods: Retrospective study of blood component use in service personnel admitted for trauma. Data were extracted from the UK Joint Theatre Trauma Registry. Results: A total of 2618 patients were identified. Survival increased from 76 to 84% despite no change in injury severity. The proportion of patients receiving blood components increased from 13 to 32% per annum; 417 casualties received massive transfusion (≥10 units of RCC), the proportion increasing from 40 to 62%. Use of all blood components increased significantly in severely injured casualties, to a median (IQR) of 16 (9-25) units of red cell concentrate (P=0·006), 15 (8-24) of plasma (P=0·002), 2 (0-5) of platelets (P<0·001) and 1 (0-3) of cryoprecipitate (P<0·001). Cryoprecipitate (P=0·009) and platelet use (P=0·005) also increased in moderately injured casualties. Conclusions: The number of blood components transfused to individual combat casualties increased during the 4-year period, despite no change in injury severity or injury pattern. Survival also increased. Combat casualties requiring massive transfusion have a significantly higher chance of survival than civilian patients. Survival is the product of the entire system of care. However, we propose that the changes in military transfusion practice and capability have contributed to increased combat trauma survival. © 2013 British Blood Transfusion Society.