A computer-simulation model of prehospital hemorrhage and fluid resuscitation was used to determine under what circumstances it is advantageous to begin fluid resuscitation in the field instead of immediately transporting to the hospital. Four hypothetical bleeding rates (15, 25, 50, and 100 mL/min) were examined for short and long prehospital times. No significant difference in survival was noted for bleeding rates of 15 mL/min for either short or long time; a small but statistically significant increase in survival was noted for bleeding rates of 25 mL/min and long transport times. For both short and long times, all higher bleeding rates showed greater survival with prehospital fluid resuscitation and higher blood pressure at the onset of definitive care.