Septic shock is the most severe systemic inflammatory response to infection. Despite recent progress in prevention and critical care therapy, this syndrome is the most common cause of death in intensive care units. Major advances have been realized recently in the understanding of septic shock. Cellular receptors involved in bacterial recognition have been identified as Toll-like receptors. After bacterial challenge, these receptors become activated and initiate in septic shock patients a biphasic immunological response associated with coagulation disorders. Genetic variability among humans and their predisposition towards pathologic inflammatory responses have also been demonstrated. These current views on the pathophysiological aspects of septic shock open new therapeutic perspectives which should change the prognosis of this syndrome.