Systemic infection due to Trichosporon beigelii is uncommon but increasingly reported in immunocompromised patients. Trichosporonosis is often refractory to conventional antifungal therapy and frequently fatal. We report a case of systemic T. beigelii infection in a patient with acute leukemia. The 35-year-old male patient had been diagnosed as acute myelogenous leukemia with severe neutropenia and received cytotoxic drug therapy. As a fever developed on the day 21 of chemotherapy, broad spectrum antibiotics were administered empirically. Even though an antifungal drug, amphotericin B was replaced because the blood cultures resulted in T. beigelii, the patient died of the septic shock. We think that T. beigelii should be included as a potential life-threatening pathogen capable of causing widespread systemic disease in the immunocompromised host. (Korean J Clin Microbiol 2002;5:151-154)