The 11 cases of malaria admitted to Kaohsiung Medical College Hospital in the past 10 years were analyzed to assess the characteristics of patients who acquired malaria parasite infection. Nine of the patients contracted malaria in Southeast Asia. Two men had received antimalarial chemoprophylaxis before they went abroad and another two men relapsed after antimalarial treatment. The initial symptoms and signs were nonspecific, including fever, chills, abdominal pain and hepatosplenomegaly. Seven patients responded well to the antimalarial regimens. Two persons developed meningeal malaria. Resistance to chloroquine and primaquine and even to quinine was noted in another two cases. Hypoglycemia was diagnosed in one of latter two patients who developed heavy parasitemia (26%), acute renal failure and died 5 days after treatment. Peripheral blood smear examination is a simple and quick method to make a diagnosis in any suspicious case. Resistance to chloroquine and primaquine is not uncommon, especially in those who acquired the infection in Southeast Asia. Changing to more potent agents and aggressive management in complicated cases is necessary.