Adult-onset Still's disease (AOSD) is a multi-systemic inflammatory disorder characterized by high spiking fever, evanescent salmon-colored rash, arthralgia or arthritis, leukocytosis and the involvement of various organs. However, leukopenia is rarely associated with AOSD. It may be due to hemophagocytic syndrome, which usually present with acute febrile illness, pancytopenia, hepatosplenomegaly, and hyperferritinemia. We report a case of 28-year-old man with AOSD and leukopenia. There is no evidence of other causes of cytopenia and hemophagocytosis in bone marrow examination. Leukopenia can be the initial presentation of AOSD.