Background: Administration of large amounts of fluids to trauma patients, in the absence of surgical control, may increase bleeding, cause hypothermia and coagulopathy which may worsen the bleeding and increase morbidity and mortality. The purpose of our study is to examine the impact of prehospital fluid administration to military combat casualties on core body temperature and coagulation functions. Methods: Prospective data were collected on all cases of moderately (9 ≤ ISS ≤ 14) and severely (ISS ≥ 16) injured victims wounded in South Lebanon, treated by Israeli military physicians and evacuated to hospitals in Israel, over a two-year period. Data regarding prehospital phase of injury (timetables, amount of fluids) and upon hospital arrival (initial core body temperature, prothrombin time [PT], partial thromboplastin time [PTT]) were examined for monotonic relation using Spearman's non-parametric test. Results: Fifty-three moderately injured and 31 severely injured patients were included in the study. The average evacuation time for the moderately injured group was 109.3 ± 44.8 min, and for the severely injured 100.3 ± 38.4 min (P value = NS). The mean volume of fluids administered was 2.39 ± 1.52 and 2.49 ± 1.47 l, respectively (P = NS). No statistical correlation was found between core body temperature, PT or PTT, measured upon hospital arrival, and prehospital fluid treatment. In addition, no correlation was found between core body temperature on hospital arrival and prehospital time, or between prehospital fluid volumes and prehospital time. The mean core body temperature of the moderately injured patients was 36.8°C, and that of severely injured was 35.8°C (P = 0.026). Conclusions: With proper control of blood loss and avoidance of excessive fluid administration, moderately and severely injured combat casualties in 'low intensity conflict' in South Lebanon can be resuscitated with fluid volumes that do not result in a coagulation deficit or hypothermia. The core body temperature on arrival at the hospital is related to the severity of the injury.