Immunophenotyping of acute leukemia using flow cytometry after density gradient separation (dg-sep) of mononuclear cells is the international gold standard. But destroying red cells by whole blood lysis (wb-lysis) after direct staining has found a broad usage. Both methods revealed congruent results in phenotyping of 26 cases of acute myeloid leukemias by testing CD4, CD7, CD11b, CD11c, CD13, CD14, CD15, CD33, CD34, CD65s, Glycophorin A and HLA-DR antigens. Mean values of these tested antigens were very similar. Only low antigen expression of CD2 was missed in the phenotype of two AML cases by the wb-lysis (23 and 29% positive cells by the dg-sep).