The authors report a case of hemophagocytic syndrome (HPS) associated with acute visceral leishmaniasis (VL). A 4-year-old boy was admitted with high fever, hepatosplenomegaly, and pancytopenia. Elevated serum ferritin and triglyceride, low fibrinogen levels, and bone-marrow (BM) histiocytic hyperplasia with prominent hemophagocytosis were consistent with a HPS. An initial diagnosis of kala-azar was refuted because of negativity of BM aspiration and serology for this parasite, and the diagnosis of HPS was made. Three months after first admission, reevaluation of the BM aspiration revealed many amastigotes of Leishmania parasites. The serology of VL became positive, finally establishing the diagnosis of VL. Although specific therapy for VL was instituted, the patient died 4 weeks after the... diagnosis.