The poor response to therapy in acute myeloid leukemia (AML) raises the expectations that the presence of leukemic stem cells (LSCs) may add to therapy resistance. Using flowcytometry, we analyzed the expression of CD123 among CD34+CD38- cells in AML patients at initial diagnosis and on day 14 post induction. We concluded that CD123 may be used as marker of LSCs in AML, presence of LSCs at diagnosis had no prognostic impact on treatment outcome and the emergence of LSCs in post induction samples may reflect an induced stem cell theory contributing further to disease resistance