ABSTRACTBackground: Immunophenotyping has become crucial in the diagnosis and classification ofacute leukemias and identification of its aberrant phenotypes. This study aimed to evaluatethe patterns in AML cases presented to the flowcytometry unit at the Sulaimani Public HealthLaboratory, Kurdistan, Iraq,and to determine the frequency of aberrant expression oflymphoid associated antigen.Subject and Methods: For the above purposes, 108 cases of acute myeloid leukemia (AML)were evaluated morphologically,and by flowcytometry with a panel of 22 antibodies.Furthermore, any aberrant expression of lymphoid associated antigens was reported.Results: The morphological AML subtyping revealed that 29.6% of AML cases were M2,while M1 (36.1%) was the predominant subtype by immunophenotyping using WHO 2008classification. CD117, CD45, CD13 and CD33 were the most frequently expressed markers(99.1%, 92.6%, 92.6% and 85.2% respectively). Forty-five patients (41.7%) expressedlymphoid associated antigens (nTdT, CD19, CD79a, CD10, CD4, CD56 and CD9) that wasdemonstrated in all AML subtypesexcept M6.CD56 was the most frequent(13%),followedby CD9 (12%), CD4 (8.3%), and CD19 (7.4%).CD79a, nTdT and CD10 were less frequent,present in <5% of cases each.Conclusions: Immunophenotyping is an essential supplement to morphology in AML,whether for confirmation or accurate subtyping. Furthermore, more than 40% of cases showaberrant lymphoid antigen expression. The latter may serve as an important tool in futurestudies on minimal residual disease evaluation.