Background: Angiogenesis is the highly ordered formation of new blood vessels from pre-existing vessels. It is seen throughout growth, in wound healing, menses and is important in cancer, where pro- and anti-angiogenic signals can be released by cancer cells, endothelial cells, stromal cells, blood and the extracellular matrix. Aim of the study is to verify the significance and prognostic value of assessing marrow angiogenesis at diagnosis of de novo acute leukaemias. Subjects and Methods: The study included 70 newly diagnosed acute leukaemia cases and a control group composed of 35 bone marrow biopsy (BMB) sections obtained from breast cancer patients. Examination of CD34 immunohistochemically (IHC)- stained sections for the assessment of marrow angiogenesis by quantification of its microvessel density(MVD) was done. Results: MVD was significantly increased in acute leukaemia patients in comparison to control group (p-value<0.001). Although we couldn't detect a predictive value of increased MVD as regards the clinical outcome in terms of achieving complete remission and partial remission, our results suggested a role of angiogenesis in thepathophysiology of acute leukaemia.Conclusion: The study demonstrated an evidence of increased angiogenesis in acute leukaemias detected by high bone marrow MVD which may play a significant role in leukaemic process. Understanding its role may help in designing new therapeutic strategies for acute leukaemias