The leukocyte differential count is one of the most useful and frequency requested tests in the clinical laboratory. Conventional blood cell counting instruments can enumerate only the WBCs normally found in the peripheral blood, i.e., neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Nevertheless, there are other cells not normally found in the peripheral blood, such as immature granulocyte. They are indicators of different disease states. We haven't got still references of automatic method to good evaluation of enumeration of the immature granulocyte. AIM OF THE STUDY: The aim of this study was compare count immature granulocytes by manual microscopy method with flow cytometric method. Flow cytometric method enumeration of immature granulocyte was performed using monoclonal antibody: anti-CD45, anti-CD11b and anti-CD16. RESULTS: A comparison of flow cytometry count with the manual count of promyelocytes, myelocytes, and metamyelocytes using linear regression revealed a correlation coefficient of 0,85 for percentage counts. CONCLUSIONS: Our results indicate that the flow cytometric immature granulocyte count can replace the manual morphology count for the laboratory work.