Background:Aberrant phenotype is a phenomenon in which lymphoid-associated and other myeloid lineage markers expressed in myeloblasts or myeloid-associated markers expressed in lymphoblasts. Occurrence of aberrant phenotype that has been reported in acute leukemias with varying frequency though its prognostic importance still remains controversial. So the aim of this prospective cohort study was evaluation the outcome of de novo AML patients expressing lymphoid markers(Ly+ AML) correlated with cytogenetic pattern and clinicobiological features.Metods: our prospective cohort study designed to evaluate de novo adult patients having primary AML with the exclusion of acute promyelocytic leukemia admitted to the clinical Hematology Unit, Internal Medicine Department, in a tertiary referral hospital in Egypt, from July 2016 to the June 2019.ResultsPatients were classified according their lymphoid markers expression into two groups Ly+ AML and Ly- AML including; 23 (29.5%) and 55 (70.5%), respectively. After a median 8.133 months (range, 0.3-26 months) as a period of follow up, Ly+ AML patients group was associated with a significantly lower CR rate (p= 0.04). Moreover, Ly+ AML patients group was independently associated with complete response to therapy with OR [95%CI; 0.12-0.98], P=0.047 by using of the multivariate logistic regression model. Regarding survival, no statistical difference was showed in 26 months disease- free survival and overall survival as well.Conclusion: lymphoid markers expression in AML patients was independently associated with Response to therapy. However, it was not reported as an independent predictor of survival.