Initial fluid management of the injured patient involves replacement of fluid lost incident to the trauma as well as prompt recognition and treatment of shock. Prompt fluid replacement based on these concepts will result in a reduction in mortality and prevention of many complications resulting from prolonged inadequate tissue perfusion. In this discussion, an attempt will be made to facilitate this approach by: (1) discussing these fluid changes; (2) presenting a clinically applicable classification of shock; and (3) outlining a rational approach to the early treatment of hemorrhagic shock, the most frequent form of shock occurring early after injury.