Wilms (WT1) is overexpressed in the majority (70-90%) of acute leukemias and has been identified as an independent adverse prognostic factor, a convenient minimal residual disease (MRD) marker and potential therapeutic target in acute leukemia.Using a real time quantitative PCR technique we examined the bone marrow of 41 newly diagnosed acute lymphoblastic leukemia patients, 19 children and 22 adults.All leukemic patients enrolled in this study showed WT1 overexpression at the time of diagnosis, 38 patients out of total 41 (92.7%). Only 3 patients had low WT1expression; 2 children and one adult and one of them entered in relapse.The expression of WT1 was found to be higher in children above ten years of age (mean expression 3.054±3.51) than children below ten years of age (mean of expression 0.185±0.399).Regarding clinical and laboratory findings of ALL patients and WT1 expression a significant association between WT1expression at diagnosis and the gender in pediatric group being higher in males than females with a mean (0.8031±1.966) and (0.332±0.855) respectively and p-value was 0.048).A significant negative correlation was found between WT1 expression at diagnosis and both HB level and platelet count in adult group, p-value was 0.044 and 0.003 respectively. While no difference between T-ALL and B-ALL was found (mean 0.585±0.885 and 0.554±1.423) respectively.Among 41 patients studied, 6 did not achieve remission. One child six months old died after 3 months, three other children entered in relapse and only two adult patients entered in relapse. MRD was detected only in four patients out of the six who did not achieve remission. All of the four were children. We found no statistical significant impact of the gene overexpression on disease free survival DFS (P=0.054).MRD at day 14 after induction therapy was done for 20 patients and proved to be correlated to the occurrence of relapse (P=0.007).WT1 is a reliable marker for minimal residual disease assessment in acute leukemia patients. WT1 helps identify patients at high risk of relapse soon after induction chemotherapy allowing post-induction therapy in high risk patients to be intensified.