BACKGROUND HPS is a potentially life-threatening histiocytic disorder that has been described in various viral infections including dengue. Its involvement in severe and fatal dengue is probably more common but is presently under recognized. METHODS A 38-year-old female was admitted after 5 days of fever. She was deeply jaundiced, leukopenic and thrombocytopenic. Marked elevation of transaminases, hyperbilirubinemia and hypoalbuminemia were observed. She had deranged INR values and prolonged aPTT accompanied with hypofibrinogenemia. She also had splenomegaly. She was positive for dengue IgM. Five days later she became polyuric and CT brain image showed gross generalized cerebral edema. Her conditions deteriorated by day 9, became confused with GCS of 9/15. Her BMAT showed minimal histiocytes. Her serum ferritin level peaked at 13,670.00 µg/mL and her sCD163 and sCD25 values were markedly elevated at 4750.00 ng/mL and 4191.00 pg/mL, respectively. She succumbed to the disease on day 10 and examination of her tissues showed the presence of dengue virus genome in the bone marrow. RESULTS It is described here, a case of fatal dengue with clinical features of HPS. Though BMAT results did not show the presence of macrophage hemophagocytosis, other laboratory features were consistent with HPS especially marked elevation of ferritin, sCD163 and sCD25. Detection of dengue virus in the patient's bone marrow, fifteen days after the onset of fever was also consistent with the suggestion that the HPS is associated with dengue virus infection. CONCLUSIONS The findings highlight HPS as a possible complication leading to severe dengue and revealed persistent dengue virus infection of the bone marrow. Detection of HPS markers; ferritin, sCD163 and sCD25, therefore, should be considered for early recognition of HPS-associated dengue.