Marrows from 58 newly diagnosed acute myelocytic leukemia (FAB-AML) patients were immunophenotyped by flow cytometry with 13 kinds of monoclonal antibodies. Marrows of 53.4% of the patients showed pure myeloid antigen expression (Ly-AML) and 34.5% displayed both myeloid and lymphocyte associated antigen expression (Ly+AML). In general, fluorescence intensity of lymphocyte associated antigen in Ly+AML was weaker than that of myeloid antigen. Myeloid and lymphoid marker cells distributed randomly in DNA-aneuploidy. It took more days to reach the first complete remission in Ly+AML. The aberration antigen expression in AML allows a sensitive detection of minimal residual leukemic cells in complete remission bone marrow and treatment stratification.