Abstract: Objective To analyze the clinical manifestations, laboratory findings, treatment and prognosis of patients with hemophagocytic syndrome (HPS). Methods A retrospective study was carried out to analyze the underlying disease, clinical characteristics, laboratory findings and outcomes of 46 patients with HPS. Results This cohort included 19 cases of HPS secondary to cancer, 11 cases of HPS secondary to infection, 10 cases of suspected malignant lymphoma based on PET-CT findings (without biopsy), and 6 cases of unknown etiology. The coincidence rate of the clinical characteristics of the patients with the indices listed in HPS-2004 criteria were: fever (100% ), elevated serum ferritin (100% ), cytopenias (93.48% ), splenomegaly (91.30% ), hemophagocytosis in the bone marrow, spleen or lymph nodes (84.78% ), hypofibrinogenemia (67.39% ), and hypertriglyceridemia (54.05% ). The cases of cancer, infections and unknown etiology showed significant differences in serum levels of ferritin and β2MG (P<0.05), and significant differences were found in triglycerides, LDH, and fibrinogenemia between the nonfatal and fatal cases (P<0.05). Conclusion HPS can be secondary to various underlying diseases, many associated with Epstein-Barr virus infection. Cancer, especially NK/T-cell lymphoma, is the main cause of HPS. Persistent fever, elevated serum ferritin level and cytopenias are the most sensitive indicators for diagnosis of HPS, and early diagnosis and treatment are critical to lower the mortality rate of this disease.