Dengue is known to cause high morbidity and mortality worldwide. In recent years, there have been increasing cases of dengue fever associated with a rare complication: hemophagocytic syndrome (HPS), which is a dangerous disorder that carries high mortality. It is associated with infections, autoimmune disorders, and malignancies. Prolonged duration of fever and cytopenia together with multi-organ dysfunction out of proportion to the plasma leakage phase should alert clinicians to consider this condition. In this case study, we highlight a 45-year-old woman with underlying diabetes who was admitted due to dengue fever with warning signs. Her conditions deteriorated quickly: she had spontaneous bleeding, evidence of plasma leakage, severe hepatitis, and coagulopathy on the 11th day of illness. With the support of other blood results, such as raised serum ferritin and lactate dehydrogenase, she was diagnosed with severe dengue with hemophagocytosis syndrome. She responded well to intravenous dexamethasone and recovered on the 19th day of illness.