Flow cytometry has became an extremely useful tool in thè diagnosis of hematological malignancies. The multitude of available monoclonal antibodies and thè routine use of multiparametric techniques bave drastically improved thè diagnostic utility of flow cytometry in thè study of leukemias. This review focuses on thè use of flow cytometry in thè routine clinicopathological approach to thè diagnosis of acute leukemias. The Authors discuss not only thè use of flow cytometry in thè differential diagnosis, but also correlate flow cytometric immunophenotyping with other cytobiologic techniques in thè study of acute leukemias