The Abbott Cell-Dyn (CD) 3000 is an automatic analyser, designed to give cell blood counts (CBC) and white blood differential (WBCD) by 4 angels diffraction analysis. Evaluation was performed by comparison between results obtained by CD and those obtained by Technicon H1 and by microscopic examination. Technical performances as reproducibility, linearity, carryover were quite well acceptable. On normal samples, neutrophils (NE), lymphocytes (LY) and eosinophils (EO) were found to correlate with optical method with coefficient (R) values higher than 0.9. Weaker R coefficients were found for monocytes (MO) and basophils (BA), however it didn't involve clinical consequences. Significant threshold for immature granulocytes (IG) and variant lymphocytes (VL) flags were built. By using those, a false positive rate of 7% was shown. In hematological diseases, no false negative was detected because all samples were flagged. However, no acute lymphoblastic leukemia (ALL) was studied, so the detection of lymphoblast, as known as a real difficulty for analyser, was not yet evaluated. Blasts in acute myeloblastic leukemia (AML) and hairy cells were both noticed by CD. Moreover, for chronic lymphocytic leukemia (CLL), three groups were described, according to the flags released. Knowing its performances and its limits, CD is a good analyser usable in an all round or a hematological laboratory with high number of WBCD per day.