Background: Patients with acute myeloid leukemia (AML) with a high white blood cell count are at a significant risk for developing serious complications and passing away before their time. Dexamethasone has been recommended for usage in AML patients because it has a strong inhibitory impact on cytokine production and modulates the inflammatory response. Objective: To evaluating the effect of adding dexamethasone to induction chemotherapy on the clinical outcome for the first time in Egyptian AML patients with high leucocyte burden. Patients and methods: This randomized clinical trial included 82 adult patients with AML with high leucocytic count, conducted in Clinical Hematology Unit, Internal Medicine Department, at Zagazig University Hospitals. Patients were divided into two groups; a control group received an induction 3+7 chemotherapy regimen; and a DEXA group received dexamethasone in addition to induction chemotherapy. Patients were followed up after receiving their treatment for a total period of 12 months to estimate survival. Results: High leucocytic count was positively correlated with peripheral blood blast, AST, creatinine and LDH and negatively correlated with both serum albumin and potassium. Early death was significantly higher in the DEXA group (56.1% vs 24.4% in control group, P= 0.003). Moreover, there was higher death, primary induction failure rates in the DEXA group (P= 0.031 and 0.007 respectively) and lower relapse rates (20% vs 53.3% in control group, P= 0.043). There was statistically significant lower 1-year overall survival in the DEXA group (overall-survival rate 10% vs 21% in the control group, P= 0.003). Conclusion: Although the use of dexamethasone in AML patients with hyperleukocytosis lowered the relapse rates, it was associated with higher treatment-related mortality and inferior overall survival with no effect on relapse-free survival.