Infection-related hemophagocytic syndrome was originally described in viral processes by Risdall in 1979. Recent reports have suggested associations of this syndrome with bacterial, parasitic and fungal infections. It occurs generally in immunosuppressed patients. The clinical and biological manifestations are not specific. The diagnosis is based on morphologic examination of the bone marrow showing a benign proliferation of histiocytes with hemophagocytosis. Treatment is symptomatic, however when an infectious etiology is found a specific treatment must be applied. This pathology has a poor prognosis, with a fifty percent mortality rate. When evolution is favorable, relapses are exceptional. The precise pathophysiological mechanism has not yet been determined. A better understanding of the cytokines' role should permit to consider new therapeutic routes.