A 14-year-old boy with fatal varicella zoster virus-associated hemophagocytic syndrome (VAHS) was treated with recombinant human granulocyte colony-stimulating factor (G-CSF) based on the finding that the patient had severe neutropenia and possible bacterial superinfection. Support for the G-CSF therapy in VAHS is provided by the recent reports that G-CSF is relatively specific for the granulocyte lineage; it would not activate mature monocyte/macrophage/histiocyte lineage in VAHS, where the most striking morphologic feature is histiocytic hyperplasia with hemophagocytosis. He responded well to G-CSF with an elevation of neutrophil counts. There were no effects on other blood cells. The result indicates that G-CSF is useful to increase granulocyte production in severe neutropenia, even in the setting of fatal VAHS.