Abstract： Objective To evaluate bone marrow smear examination in early diagnosis of AIDS complicated with disseminated Penicillium marneffei infection. Methods Seventy-three clinically suspected AIDS patients complicated with disseminated PeniciUium marneffei infection were included in the study. Peripheral blood and bone marrow smear examinations, and the fungal thermally dimorphic culture were performed in all cases. Results PeniciUium marneffei infection was identified in 44 patients by peripheral blood and bone marrow fungal thermally dimorphic culture. The features of the bone marrow smear were as follows : they were all hyperplastic or significantly hyperplastic; there were thickened and increased granules, vacuolization and band-formed in most granulocytes; there were increased and augmented histiocytes, and increased plasma cells. In 12 samples of bone marrow smear, there were phagncytized mulberry-like Penicillium marneffei organisms in the cytoplasm of the histiocytes or the organisms found extracellularly. One sample demonstrated the increased granulocytes and the phagocytized organisms in the neutrophils and monocytes. In 4 samples of peripheral blood smear, there were phagocytized Penicillium marneffe organisms in the neutrophils and monocytes. Conclusion Bone marrow smear examination is of value in early diagnosis of AIDS complicated with disseminated Penicillium marneffei infection, which is 7 to 10 days earlier than routine fungal thermally dimorphic culture.